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independent study » Yekaterina Satanina
May 202015

This is the last post of the semester long Houdini independent study project. But hey – it ain’t done! It ain’t done, it ain’t done. And I’m not done. There is way too much I want to do with this program. Many more projects will come.

For now, here are the last things I did.

This is what the bonfire looks like. I’ve varied the proportions, amount of deformity, twist, taper, and bend of the logs, as well as added more branches to flesh it out. The hope was to mask most of it with the fire effect on top, but that didn’t happen, and I’ll get to why later.


Underneath and around the fire I scattered a bunch of ashes. Made in a similar way to the big rocks.


I wanted to put a layer of snow on the flattest areas of the landscape using metaballs. It would be unrealistic for computation times to scatter thousands of metaballs all over the entire landscape, so I only picked one area, and used the super handy slope attribute calculated earlier to scatter points just on the flat planes.


Then copied metaballs onto those points. It looked pretty much like what I wanted from up here…


…but not from up close. This just won’t cut it. This is mostly a problem of my scene scale. I’ve made the terrain a lot smaller than it normally would be, thinking this would decrease computation times, but it made any effect difficult to bring to realism. Everything I tried adding looked slightly miniature: the metaballs, the particles, the fire, etc. – even when scaled down.


So I tried scaling the metaballs way down, increasing the number of scattered points way up, increasing the resolution of the resulting polygon mesh…

And then Houdini crashed several times, leading me to believe that I overdid it with the metaballs. So instead, I focused on just that focal area, and made some nicer-lookin snow around there.


And then added the shaders to everything. Shading is something I’m just beginning to get into inside Houdini, so these shaders are fairly basic for now. Here are the final renders.

snow10  snow12

I tried fiddling with fog: filling a volume with metaballs, making them render as fog, manipulating them with various noises to give pleasant variation and clumps.. and it worked to an extent. I also tried adding fire and smoke to the bonfire. It.. did not work.

And here’s my big mistake. Scale.

I haven’t figured out how to adjust the global scale of everything, haven’t found where/how to do that. As I mentioned earlier, my terrain is about 100x smaller than it should be. This, in turn, means that anything I add needs to be scaled way down – and effects such as fire and smoke just don’t work that way. You can’t scale down a fire effect and expect it to behave the exact same realistic way that it would when normally sized.

So that’s the result of my semester. Some successes, nothing great, nothing too pretty, but a lot of lessons. Here’s what I would do differently in the future:

1) Appropriate scope. This project was trying to achieve too much in too little time with too little knowledge. I already know what I want to do next – a bonfire. Just a medium shot of a nighttime bonfire. But I want to make it good, really really good. This environment was just.. too big. Too much.

2) Appropriate scale. Figure out the scale of the scene before starting.

3) Focus on what Houdini is best at. I personally really wanted to do procedural modeling and set dressing – and honestly, got a kick out of it! Loved it. But Houdini’s forte is effects, destruction, explosions, water, fire, realism. I should really learn that.

And that is that. I graduate in two days. And I have tons of things I want to do, this being just one of them.

May 052015

This week the trees are finally sprouting leaves and flowers in Rochester. I started learning about L-systems this week. Coincidence? Pre-planned? Coincidence. But appropriate.

These things, right here!

L-systems are recursion. Visual code, just like our very first Python project in Computer Science 1 class. They’re a rewriting system, consisting of an alphabet/vocabulary of symbols that make rule strings, and grow with each generation according to those rules. They can be very rigid and architectural, or organic and random. Very versatile; both design-y and artsy. But based on math, and created by a biologist/botanist. Often used to model organisms.. molecules.. fractals.. plants. Many other things. I got excited.

I’d say this here is a pretty darn good example of generations of a growing plant. Fairly random-lookin, fairly organic. If I can learn that, ‘twould be cool!

Why do I need L-systems all of a sudden? For the focal point of my piece – the bonfire. Branches, twigs. To start, I quickly mocked up some logs and arranged them in a bonfire:


Now I need to make me some branches.

I’ll make this post into a handy reference for myself, for future endeavors involving L-systems. As I said, L-systems are created based on rules. There’s a base, then there are rules defining the iterations.

Example base:    X

Example rule:     X = ! /(3) T F[+X] ~F[-X] +X : 0.4

Unlike regular algebra, each symbol is read and interpreted left to right. This one would read as: the thickness decreases, as the limbs roll 3 degrees counterclockwise, and curve down due to gravity, do a step, twist randomly, do a step and another turn and step – and the probability of all this happening is 40%. The (not full) syntax broken down is:
F   —> full step
H   —> half step
  —> full step, no line drawn
h   —> half step, no line drawn
+,   —>  turn right, left; recursion in 2 dimensions (flat)
&, ^   —> pitch up, down; adds rotation in the third dimension
\, /   —> roll clockwise, counterclockwise
[ ]   —> the start and end of a side branch; “push and pop” (because that makes more sense to me, in CS stack terms), allow for backtracking (node rewriting)
T   —> tropism (curvature) – adding a curve to the branches. The definition of tropism is: “the turning of all or part of an organism in a particular direction in response to an external stimulus.” And that makes sense because, you know, L-systems can be used to describe molecules and other biological things.
”   —> multiplier of curvature
!   —> multiplier of thickness
;   —> multiplier of angle
~   —> turn a random degree

Here’s a much more thorough list of commands: http://www.selcukergen.net/ncca_lsystems_research/houdini.html. And and even longer but thorougher explanation, straight from the SideFX website: http://www.sidefx.com/docs/houdini10.0/nodes/sop/lsystem.

So let’s do something. There are two methods of creating L-systems: 1) edge rewriting – replacing edges with the recursion, and 2) node rewriting – appending recursion to the last node.


This Koch star, which started as a triangle, is an example of edge rewriting, as the edges get more complex with each generation. Fun fact: adding a Revolve node to the resulting curve is fun. Or, you know, not stopping with the L-system and actually creating something interesting using it as a stepping stone. (Which is how it should be done.)


And this is a simple example of node rewriting, where the structure actually “grows” with each generation. Very simple rule up there – each time you see a full step, replace it with: a full step, a branch turned right, another full step, a branch turned left, and a third full step.


This example introduces variables – symbols outside of L-system vocabulary that are defined by the artist in the rules. These variables are just another “full step,” but you get to make whatever you want of it. Easy, right? Easy..

But then you add the ! for thickness, to get the branch to thin out on top, and the T for some sagging of the side branches, and for curvature, and ~ for twisting, and add values in parentheses like (15) to specify the angle/value of turning/manipulation, and get it more and more and more complex and cool!


So I was already happy with my branch at this point: it had quite a lot of variation and twist to it, looked fairly organic overall! And it doesn’t even include any probability rules!

Probability rules?

If you add ‘:number‘ to the end of a rule (like this: X = ! // FF [-X] F [+X] F : 0.8), that number becomes the % of the time that rule gets executed. Randomness!

And there are, of course, conditionals – if statements. F: t>number = rule means execute the rule if the generations are greater than the number specified. Very very cool for structures that age.

  —> or
  —> and
Example: F: (t<3) | (t>6) = rule

But that’s not all. The L-system node in Houdini has four inputs up top, labeled by letters of the alphabet. They’re there for copying geometry onto the ends of branches! Hello, fruits, leaves, atoms, or whatever else your heart desires on the ends of those branches. I quickly threw some randomized berries on my tree, just by taking a sphere, mountain-SOPing it, scattering points on the deformed thing, and copying a little-er sphere onto each scattered point. And plugging that into the J input of the L-system:


Neat. I like it!

The possibilities here, oh man. It would probably help me, being a visual person, to draw the shape of the tree/system/object I want, then figure out how to make that pattern, what building blocks go into it – and then translate that “pseudo code” into L-system rules.

But this was enough for me to make the branches for the bonfire. Here’s what I ended up with. It’s not final, but I’m happy with the direction it’s going:


Next up: the fire and the smoke.

Apr 162015

I started (finally) looking for jobs. Came across qualifications for an effects artist (mind you, I am not ready to apply to those, and won’t for some time) – and found more motivation to be learning Houdini. When The Mill representatives gave their presentation at RIT several weeks back, so many of their process shots included the Houdini interface. Two days ago, Paul Hildebrandt from Disney gave a talk on their technical pipeline and tools – and hey, guess what, there it is. I was excited to hear that Disney effects artists write calculus equations all over their whiteboards. On the other hand, it was encouraging to hear that yet other artists draw their effects out on paper before they go into 3D space. There’s hope!

This week I explored particles in Houdini and played around with the different POP forces. Made this!

Figured out how to have one force (curve force) affect the particles up to a point, and then when they reach a certain age to be affected by a different force (combination of axis and attract forces). Added color and opacity, and tried to figure out how to render the whole thing. Alright, the preset “dust puff” shader looks okay.. but let’s try to tweak it! I opened up its network and saw this:


And decided to save that exploration for another day.

However, I feel a lot more confident with particles in Houdini now. With that, back to rocks. Hey, I made those work:


I took a slightly different approach. Before scattering points on the geometry, I grouped the areas of the landscape by which way their normals were facing – and copied rocks just into those parts. Now, I was battling with the elevation attribute. I would like to spread more rocks in lower elevations, and less up high, but I just could not figure out how to reverse the elev attribute (right now it puts more rocks in higher elevations). For now! I’ll figure it out eventually.


Additionally, I decided to revamp the up close texture of the foreground. Before it just had a mountain SOP on it, which did the job, sure, but I wanted to see if I could apply what I learned from sculpting the individual rocks to the big landscape. Attribute VOPs are not so scary anymore. I took a bounding box to isolate an area of the foreground (because not all of it needs to be super detailed all the time, and I can move the bounding box with the camera if I have to), and did this:


There is a slight, medium-scale Worley noise (I wish it was sharper), a vein pattern (which should also be sharper), and a small-scale turbulent noise for smaller detail.

Also, there’s snow:


Just need to figure out how to render the snow… Tried applying some shaders to particles, came up with some interesting but not great results, will keep experimenting.

One last thing about the rocks: I did get the attribute VOP working! Grouping by normals is a working solution, but not the most elegant one. Here, I multiplied the height of the landscape by the curvature attribute, getting this map:


Just.. have to… get the color attribute… to control the density of the rocks.

I lied, here’s the last thing about rocks. Well, it’s about shading the whole piece. I used the groups I got from the geometry’s normals to drive shaders (a very basic placeholder stone shader for both the ground and the snow). Sure, it worked, but…


… but grouping by normals gives me very unnatural jagged polygon edges. Ideally, I’d use that black-and-white map from above to control where the snow goes… but once again, that will take me just a little bit longer to figure out. This closeup definitely shows that the “grouping by normals” method for shader assignment definitely does not work:


Looks kind of nice as an extreme wide shot, though.. with the sphere-y snow.


Apr 062015

I spent my spring break in Utah this year. Came back last week. It was warm and beautiful, and a wonderful chance to get away and clear my head. However, everything there seemed to have been generated in Houdini:


So I was, of course, inspired. Would take me years to produce results that look anything remotely like these landscapes, but we’ll get there eventually.

All the locations we went to (Slot Canyon, Arches, Bryce, Zion) looked so different! Different rock formations, different textures. Very cool Stuff. I was taking mental notes on what different rocks look like out there in the real world.

When I tried looking for a tutorial on rock generation in Houdini, I came up with nothing. The only resource I was able to find was an example file from a user on a forum (http://forums.odforce.net/topic/10798-procedural-stonesrocks/), which I proceeded to dissect to figure out what they did.

Let me explain what I did first, though.


I went with what I knew: scattered boxes copied onto the terrain mesh and displaced with a mountain SOP. The spread of good, size variation was nice, but the geometry did not look like rocks. This would work well enough for the midground and background, but for the foreground I would need a much better solution.


So instead, I found that example file and dove into it. Looks effective, but upon close inspection, not that difficult. Box, mountain SOP to shape it, subdivisions, then an attribute VOP with parameters changeable by the artist to displace the rock. Inside the VOP, a network of three different noises added on top of one another for a layered effect: Worley noise gives the rock its shape, turbulent noise adds texture, and veins (an option from the “patterns” menu) give the rock some cracks. Makes perfect sense!


The parameters outside the VOP, which allow the artist to change the look of the rock, include the offset of the Worley noise, Worley scale, the amplitude of the additional (turbulent) noise, depth of cracks, and the spread/amplitude of the crack pattern.

So I started making my own!

I wanted to try a different noise pattern for the overall shape of the rock, but none worked quite as well as Worley did. After doing some research, I even came across an article that said that Worley noise is best for stone and water textures. I kept it in.


I also tried different kinds of noise for the secondary texture and other patters (crackle, oscillations, ripples, etc.) for cracks, but… did not find a more pleasant combination than the one in the example, yet! Although I believe if I spend more time and figure out how to make the ripples work, they might look nicer and more natural than the default “veins.”

When the rock was done, I tried plugging it into my prior setup, and realized that this technique won’t work anymore:


The solution for that is adding variables to the copy SOP and using a transform node to randomly rotate and scale the rocks. Later I’ll take this one step further and randomize the rocks’ noise displacement offset, amplitude, and crack values.


Looks better! Now I just need to figure out how to arrange the rocks according to the curvature of the land, and not just randomly everywhere. I found a measure SOP that measures curvature, but that alone did not do the trick. It began to clump the rocks in certain areas, but did not give me any control over the precision of the placement:


I could, I guess, just take these rocks, separate them into separate volumes/meshes, and simulate them falling…

But let’s try this first. After the measure SOP, I added several attribute VOPs and inside each one calculated the slope of the landmass and used the color channel to represent the slope/curvature values. This method allowed to determine the peaks, the valleys, the steepest slopes, and the flattest areas. In theory, all I need to do now is take this color information and apply it to the scatter SOP so that the big boulders would only be placed in certain areas, the trees in others, grass and small pebbles elsewhere…


And this is the missing link that I haven’t figured out yet. How to take that color channel and make it affect the scattering of the rocks.

Also, once I figure this out, the same color information would be very useful in assigning shaders – the snow shader will go on the flat areas, and the stone shader will do to the steeper slopes. Speaking of which – I have found zero tutorials on either snow or stone shaders.

But hopefully I can figure something out myself. The general idea for all this is sensible: layered noise. Unfortunately, it takes me hours to figure all of this out.

To be continued!

Mar 172015
Good news! I tried breaking a shader and it worked. I should stick to tutorials for the time being.
But yes. I tried out Houdini’s shading this week. I like it. It’s pretty. But it’s also really dang complicated! Which, of course, makes it insanely powerful and infinitely customizable. But also very very easy to break for little me.
First of all – Houdini’s IPR rendering is fast. And I can drag and drop materials onto objects straight in the render view instead of going back and forth between multiple windows! Mind blown, just a little. Shaders are constructed out of nodes (of course) inside VOP networks. On the surface – simple. Looks similar to the Hypershade. There’s your diffuse, there are the U and V coordinates, there’s SSS, all in the Surface Model node. Unlike the Hypershade, you have access to everything, every parameter, even the hidden ones. You can organize them as you see fit and save shaders as modular and modifiable digital assets.
So, naturally, with all this freedom and control, the first thing I did was break a shader and crash the program.
There are three main shader options in Houdini:
1) Mantra Surface Shader – big “uber shader”, very customizable, can and should be used without altering the VOP network. Similar to the MIA Material – just go in and change slider values. The nodes on the top level of the Mantra Surface Shader VOP are digital assets, so there are even deeper levels. Here is just its topmost level:
2) Surface Model – a “bare bones” shader, as Side Effects describes it. Fast, a good start for building your own shaders. Specular, diffuse, and other basics are already there (those promoted parameters in the Surface Model node), but any complexity needs to be wired in. Similar to a Blinn, I think!
3) Material Shader Builder – where everything has to be connected from scratch. This one starts out as a flat, constant color, like Maya’s Surface Shader – no surface model node inside its default VOP. Got to do everything yourself, kiddo.
Houdini also has some handy presets all ready for playing around with – glass, chrome, wood, stone. Stone! That’s relevant to what I’m doing. Let’s look at the VOP network, because I can, and see how it’s made:
From what I understand, this shader has several layers of color and noise. Take some turbulent noise, with “splatter” (more noise) on top, multiplied with two color nodes, add spec, add emission, add opacity, add displacement, put all of that into the Surface Model node. Most of the available parameters are promoted so the artist can tweak them. One of the noise parameters is responsible for dirt; the two color nodes are stone color and pepper (detail) color, there are tabs for reflections, emission, opacity:
If I wanted to add more layers to the shader – say, marble-like veins, or a different mineral deposit inside the rock – I could probably wire in more noise, turbulence, splatter nodes (different types of noise nodes) and intermix them with the existing ones.

Thankfully, hovering over just about anything in the VOP network tells you what it is, what it takes as an input, or what it produces for an output.


So a question that has been bugging me is: just how many different kinds of noise does Houdini have, and what are they all best used for?

Here’s an example of 3D noise being used for color, texture, and displacement:

I kept thinking, “Autodesk has a wonderful documentation – a command reference. Houdini has… lots of nodes.” But eventually I found this: Houdini Nodes Quick Reference – an 87-page manual on nodes! The best part is that it’s not searchable at all. (Sarcasm.) But I am actually thankful that I found it, and should make some light bedtime reading out of it.
But I digress. Noise! There are many noise nodes accessible just from inside a VOP network. I hope that over time I’ll know which one to use for which purpose. Some noise is only 2D, some can be 2D or 3D, some has more customization abilities, some – less.
Voronoi and cell seem to be very similar, but cell noise has borders. Worley noise (not pictured) seemed to be just like voronoi. Unified noise, also not pictured, seems to be a combination of flow, periodic, worley, and several others. Like Pyro noise, it has lots of parameters and customization options. Turbulent, bump, and anti-alias are all very similar looking, but some (bump) are just 2D and others (AA) are 3D. High-low noise has the most distinct look to it, of just scattered specs.
Hopefully in time I’ll know what each does best.
Mar 102015

Yesterday and today, the temperature in Rochester is in the high 30s (almost 40!), and we all went nuts and brought out the shorts and dresses. It’s the little things in life.

Meanwhile, I began working on my project’s composition:


And I don’t like it!!

Let me clarify: I love the process and enjoy it immensely. I like trying to figure things out, try this node, that node, this technique I remember, etc. No – so far I don’t like the result. But I’ll keep working on that.

Big thing I realized: the nature of my process makes achieving my goal a bit tricky.

For each layer, I start with a 2D map – be that a topo map, a noise map, or anything else. Then, by assigning height attributes to the maps, I create the 3D landscape. THEN I see the resulting composition – not when I’m creating the 2D map. And when I see the result, it is not exactly what I want. So in this scenario, I must go back and forth to try to get the values to do what I want them to do.

Not the most efficient process.

I could sculpt on top, and I WILL sculpt on top, later, for details – but the goal here is to stay as procedural as I can. So I will be looking for more ways to create my landscape.

Later! For now, I’d like to catch up to speed with the rest of what Houdini has to offer: shading, particles, and lighting.


But in the meantime, let me explain what I did for the landscape so far.

For the mountains way in the background, I used the noise generation technique with some sculpting on top. For now, kept it low res. The forms are organic enough, and have the right amount of detail for the distance. All I do is tweak some settings and see if I like the result.


For middle ground mountains, the focus mountains, I used a height map. I want as much control as I can get for them, so a height map works well. This is a good base for a detail sculpt on top later. However, I’m not quite happy with the composition of these two mountains quite yet, so I’ll fix that before I sculpt.



That node tree is fun.

For the foreground land, I also used a height map, but a much simpler one. Just as a base. I then converted the foreground to a volume for adding details on top later: arches, towers, cliffs, rocks. And, of course, sculpting on top.



And this is me cheating the 3D space:


All this dense geometry – and no lag. Absolutely no lag. I am really enjoying being able to tumble around in 3D space without any lag or fear of crashing.

Mar 032015

Time to explore more cool things! Time to make more 3D out of 2D. In this post I’ll explain more terrain-building methods: generation of terrain from a 2D noise pattern and the use of volumes to create interesting formations in the landscape.

This software is both magical and simple. Magical in the way it processes data so quickly and effortlessly, magical in the design of its interface, and magical in the limitless possibilities the node-based system allows.

On the other hand, however, it’s simple. It makes sense. If I want a circle extruded along a curve, I will connect those nodes (‘circle’, ‘curve’, ‘merge’) in the proper order and manipulate their attributes to get the result I want – something that, in Maya, can be done with a lot less clicks simply by choosing “extrude.” In that sense, Maya is way more magical than Houdini: its processes are hidden from sight, and it would take some digging to unearth and see exactly how something was done. Houdini has it all right there: this is what you did, this is the result.

And nothing is “out of the box.” Not even the math. Not even the simplest noise!

Which brings me to the meat of this post. (The protein of this post?) The last method of 2D-to-3D landscape generation offered by the Go Procedural tutorial is the noise-based terrain. The method goes like this:

  1. Create a 2D noise pattern in the compositor
  2. Use edge detection to add small details to the pattern to the Nth degree
  3. Composite the pattern with custom shapes and other details
  4. Convert to 3D by projecting onto a mesh

In this example, I used a VOP COP, which is a fancy way of saying “compositing operator in VEX language.” VOPs create VEX code through the user’s manual wiring of nodes together. They’re the “underbelly” of a node that artists generally don’t see. Inside the VOPCOP generator, you can wire together a pretty complex math scenario that would make you some neat and complicated.. noise, for example. Or some other pattern. Or a shader. Many things.

And that pattern inside the VOPCOP generator can be infinitely unique and complex! Just add more math.

With my example, the x and y positions of a grid are wired into the position values of a Voronoi noise generator. Anti-aliasing is multiplied with the noise, a clamp is tacked on. Several multipliers allow the user to increase values, amplify attributes, and adjust the global scale of the noise. In Houdini, parameters are “promoted” to be visible to the artist on top, not inside the generator, so that the artist can control things like frequency, amplitude, roughness, scale, etc.


After creating the basic noise, an “edge detect” node, composited on top and blended with the original noise, adds little details.


The final composite has adjusted levels and a blurred mask on its transparency.


The geometry (grid) gets an “attribute from map” node, which takes the 2D composite and applies the chosen image parameter (in this case, luminance) to an attribute of the mesh. Another VOP, an attribute VOP, lets you go inside the mapper and wire the luminance of the black-and-white noise image to the Y-position of the points of the grid. A promoted multiplier value allows changing the elevation scale later.




The output? A detailed and easily editable polygonal mesh that can be exported as is, sculpted on, or converted to volumes for further work! Work like arches and caves, which is what I did next.

* Quick caveat: I’m figuring this out as I go. My explanations of Houdini inner workings might not be the most accurate. I still get confused between CHOPs and SOPs and DOPs. *

For arches and caves, a grid would no longer do. Instead, we use VDBs. And to my chagrin, VDB is “just a name,” according to the OpenVDB website. (They offer several very meaningful interpretations, such as “Voxel Data Base”, “Volumetric Data Blocks”, and “Volumetric Dynamic B+tree”.) What all this means: volumes in the form of voxels. A VDB node fills the space taken up by objects with voxels. In Houdini, because VDB support is added in addition to all the original stuff, VDBs require their own processes. For instance, instead of a regular “merge” node, a “VDB combine” node would be used for a Boolean-type operation between volumes.

So! We have a grid, we convert it to a volume. We make an arch from a simple torus with a mountain SOP on it (similar to Maya’s deformers), convert that to a volume, and combine the two with a “union” operation. Booleans, except smarter, because the voxels filling up the volume get recalculated once two or more objects are combined. Therefore, instead of an ugly “Boolean-type” result like this:


We get something more organic and sensible, like this:


For a cave, similar stuff. Circle extruded along a curve, a deformer node to make it look nice, and then a “difference” operation on the VDB combine.


Here’s what it looks like at the end:


What about a more detailed cave, though? What if the camera had to fly inside?

Well, friends, here’s just that.

1. Intersecting NURBS curves create the basic shape of the cave passageways.

2. Through some Houdini “magic,” or rather non-magic, a lofting/extruding operation on a circle gives the curves cave proportions.


3. Conversion of the NURBS surface to polygons.

4. Distortion of the surface with a mountain SOP to give an organic feel.


Next, more vocabulary lessons. Caves have different kinds of speleothems inside, or cave formations, made from mineral deposits. Stalagmites are the formations rising from the floor, and stalactites are the icicle-shaped pointy teeth from the ceilings. Here they are:

5. Selecting just the points of the cave whose normals are facing directly down and scattering some cone objects copied onto those points.


6. Doing the same thing for up-facing normal, and varying the cone dimensions with coded expressions.


7. After a VDB conversion and combining, here’s the result from inside the cave.


And, because this example just asks for a fly-through, here’s a fly-through!

Of course, this is nowhere near final, and needs a lot of cleanup – like clamping away those pieces of speleothems that seems to be “floating” in the air. However, for a simple concept, I think this is a pretty cool result.

But Kat, this is all great, but where’s YOUR project? How is that doing?

Well, I am sculpting the background and midground mountains this week, and will populate the scene with rocks and make the foreground land next week! And in the meantime, watch more tutorials on modeling and start some on shading. It’ll happen.

Feb 242015

Let’s talk about fun things.

Houdini is clearly capable of some powerful and pretty stuff when it comes to terrain. I found several examples of that. This looks a lot like what I have in mind for my mountains:

(Source here)

This is more of a closeup, with plenty of detail and nice randomization happening:

Houdini procedural terrain and more from Andreu Lucio on Vimeo.

And here’s a test showing a big chunk of land created, similar to the size of what I’m hoping to make:


I conclude that it’s all doable.

When I looked into methods of building terrain in Houdini, I found several different approaches, ranging in technical level and amount of proceduralism. Go Procedural, Side Effects’ own Vimeo page of demos and tutorials, gives a very thorough outline of how to go about it:


According to this workflow, straight from he software specials, terrain building can be broken down into several simple steps:

  1. Generate procedural base terrain
  2. Customize it with masses, details, and set dressing
  3. Convert the entire scene to polygons for rendering.

The first two steps, in turn, can be done in a variety of ways. Generating the base terrain can start straight from 3D, in the cases of:

  • Sculpting the geometry
  • Creating custom masses (for separate rocks)

Or you can start off with 2D data and convert it to 3D mesh, such as with:

  • 2D topographical curves (height map)
  • 2D DEM maps
  • 2D fractals and other patterns

I tried sculpting first. Sculpting is fun, always. And in Houdini, sculpting is easy. Reminded me of Mudbox. Nondestructive, easily modified on any level, just add a new subdivision node and a new sculpt node on top and keep going.


Houdini also did a good job of reducing the mesh while maintaining detail.


But this can barely count as “procedural.” However, sculpting on top of a preexisting base mesh would be a good way to add custom detail with precision and a lot of control. Note to self.

Next I tried the height map method, which also turned out to be very customizable. Sure, you can go find a real height map online and use that, but you can also draw you own:


I like this idea, because this way I can create my landscape exactly how I want it. Control over everything. The only drawback – it would be fairly time consuming. After converting the 2D curves into a 3D mesh with some attribute coding, this is what I ended up with:


It doesn’t look very detailed because I didn’t have a lot of curves to start with. Still, I liked the results. With some tweaking, extra details, and sculpting on top, this method would work for my project.



One more thing the tutorial I used talked about: the topology curves method separates the input data from the geometry generators. Generators – groups of nodes doing one function in a scene – can become digital assets. Houdini makes good use of “digital assets,” and makes it easy to save them, export them, customize them, and reuse them. Much like your own presets. Digital assets increase productivity through such reuse. Modularity!

The next approach I tried used DEM maps – digital elevation models. They are similar to height maps, but instead of curves, there are gradients. And gradients can be powerful when they drive the right things. Using Houdini’s compositor, which behaves very similar to Nuke, I took a DEM image I found online and made its luminosity drive the height of a grid:


The results of this are most realistic, but least customizable.


Also, better watch the pure white and pure black areas – those will need some exposure adjustments on the 2D composite, or 3D detailing on top.


However, there is a way to change this to a degree. The 2D map can be turned into a composite image with other details on top. For example, this screenshot shows two areas of elevation that were added with curves and assigned heights, and integrated into the rest of the terrain:


In addition to all the terrain building, I tried some procedural set dressing, and learned a new word. “Scree” is a mass of small loose stones that cover the slope of a mountain. And I’ve generated some scree on my landscape.


These points are being driven by a snippet of code that determines the slope of the geometry and places points within a certain range. In other words, the points are being generated where the landmass is the flattest. They are then randomized (scattered) a bit, and assigned a piece of geometry – in this case, just a box.


If the red boxes were rocks, and then if a different slope range controlled bigger (or smaller) rocks, and another slope range controlled more rocks – I’d have a nice, natural-looking rocky landscape. Also, this method would work great for trees, when I need to place them just on the flat areas of a landmass.


In conclusion of this part of terrain building, I have a pretty good idea of how I’ll model my mountains later this week. I’ll use a combination of all three methods – a DEM map with some adjustments for the background mountains, a unique height map for the foreground mountains, and sculpting on top for close up details and camera details. Plus, rocks and trees.


To be continued with more terrain-building methods, soon…

Feb 152015

Having given it a bit more thought and time, here’s what I actually plan to accomplish this semester.

My design challenge is to create a procedurally modeled and shaded landscape with several different effect simulations. It will be a mountain scene: terrain, snow, rocks, and evergreen trees. There will be a bonfire with smoke rising into the sky, and snow – all of this affected by gusts of wind.

To break that down, there will be elements of:

Procedural modeling: terrain, rocks;

Procedural set dressing: trees, rocks;

Shading: snow, ground; and

Effects: fire, smoke, wind, snow.

All of this will be done in Houdini, which I will learn in the process. In other words, by the end of the semester I would like to be proficient in Houdini modeling, shading, and several different types of effects – in the form of a presentable (hopefully) project. We’ll see how far I can get! Here are some composition ideas I’m playing around with:



The fire in the second concept piece will definitely make its way into the final project. Ideally I would have multiple shots, but I’ll focus on just making one good 10-30 second shot.

Right now we are beginning week 4 out of 15 in our spring semester, and here is my plan of attack for the next three-something months:

Week 4: tutorials (modeling, particle effects), testing

Week 5: modeling the terrain (background), tutorials on shading

Week 6: modeling the terrain (background and foreground), tutorials on lighting

Week 7: modeling and set dressing the rocks and trees

Week 8: modeling and set dressing some more, tutorials on effects

Week 9: shading (terrain)

Week 10: shading (snow)

Week 11: lighting, effects (fire, smoke)

Week 12: effects (fire, smoke, snow, wind) <- in that order of priorities

Week 13: finish effects, render, composit

Week 14: render, composit

Week 15: (buffer week) render, composit

So uh… I start tomorrow.

Feb 102015

I am in the last semester of my undergraduate program. There’s much to be done. There’s the thesis film, there are classes, jobs, freelance projects, and there is more learning and discovering.

And while I still have access to free software on the lab computers, I might as well…

So I’m in this 3D Digital Design class, called Advanced Studio, taught by Shaun Foster. It’s all about research and discussions on technology and design, workflows, and tools. At the core of the class is a semester-long independent study project of our own choosing. Great, I can sit in my comfort zone all I want! But no, not really. Ever since my summer internship at Pixar, I’ve been craving to get to know Houdini better.

Great. So, Houdini is a powerful tool for any kind of effect or simulation, and that’s what it’s mostly used for. However, it has strong procedural capabilities for many stages of the 3D pipeline.

I watched a fellow intern and friend, James Bartolozzi, do amazing things with Houdini during our time at Pixar. He used it for far more than just particles and effects – he used a simulation to drive the motion of a school of fish, and made it interact with interfering objects (sharks). He built this impressive and visually stunning quartz cave environment, using just Houdini for everything but rendering:

After our summer internship, James went on to intern at Side Effects, coincidentally. No surprise that they took him in to make more wonderful things with their software. During his time there, he created this piece, the Hive, entirely in Houdini:

All of this showed me that here, in front of me, is a tool with many possibilities and untapped potential. And I’d like to explore it.

This semester, I’m making it my goal to learn Houdini, and use it to create a scene with a procedural environment and effects.

It won’t be the lofty goal that I wanted to do initially – not the monstrous integration of Houdini, ZBrush, Katana, and Nuke with a renderer that I’ve never used before. That would have been nice, of course. However, there is no way it would be possible for me to complete such a task in a semester when I have so many other things at hand. Therefore, I’ve scaled it down to just Houdini (and perhaps some Nuke for post if I have time), and exploring proceduralism and effect simulation within the software.

I’ve looked into some other 3D programs that could potentially tackle such tasks. For a while, I was set on Vue. Vue looked like my dream come true: making gorgeous painting-worthy sprawling landscapes in 3D. I’ve read reviews, interviews, and random views on Vue (see what I did there?), and it seemed as though most people who’ve used it praise it. It is used in the industry a lot, judging by the number of studios and films implementing it. However, there are some downsides to Vue, and ultimately, personal reasons why I chose not to go with it.

Vue is a tool to make matte paintings in 3D. It is used a lot in conjunction with Photoshop, Nuke, and sometimes Maya. Most of the people saying wonderful things about it are concept artists or matte painters. From this, I deduce that it is more an artistic tool than technical, and that’s why I chose not to use it. As a TD, I find it more worth my time to learn something technical that goes against the grain of my thinking and pushes me further. I can make pretty pictures on my own time. For this opportunity to learn and expand my skill set (and branch out into realms beyond traditional modeling and set dressing), I would rather choose something to challenge me.

Besides, it looked like most terrain-building tools came with lots of presents and required little technical prowess, and frankly, often appeared cheap in the quality of their renders.

So I’ll be using Houdini.

As for what exactly I’ll be doing: mountains. Here are some inspiration images that I’ll be going off of:




Mount Rainier National Park

I can’t promise that I’ll make something as magnificent as Mount Rainier, but I’ll give it my best shot.

Coming up next: concept art for the project and first Houdini tutorials to figure out what’s going on.