Archives For Houdini

3Delight volume rendering

November 16, 2019

3Delight for Houdini Volume rendering test.

Adding vdb vel fields to FLIP

November 16, 2019

Using vel fields to control the flow of FLIP sims is quite the handy trick, and using the new source volume nodes set to “pull” allows you to add in your vel fields without them looking like they are taking over the sim completely. Here’s a hip file too: directable_FLIP.hiplc

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Just an update, I’ve compiled the for the latest production build, and zipped up for you lazy assholes.  Houdini_USD_17.5.258_Win_x64

I had a great time playing with Katana, and setting up a nice demo scene using my good
friend Filippo’s VDB caches. 3Delight is killing volume rendering!
https://www.3delight.com/documentation/display/3DFK/Volume+Rendering+Example

I know most of you aren’t interested in this, but hey, there has to be at least one other dickhead out there that wants to compile the USD Plugins for Windows.
We need to install a couple things, namely Microsoft Visual Studio 2017 Community, and also CMake. Get them below. When installing Visual Studio grab all the C++ add ons.

Microsoft Visual Studio

CMake

Okay, so lets get to it. We need to grab the houdini toolkit folder, located in;
“C:\Program Files\Side Effects Software\Houdini 17.0.459\toolkit” for example. Copy and paste the toolkit (and obviously all it’s contents) to somewhere. I have whacked mine in here: W:\dev\toolkit but put it wherever you want. We need to set a couple environment variables in order for everything to work.

env.JPG

Let’s make a new environment variable and append the path variable. Remember this is the “User variables for YourName” section, not the System Variables. Make your new var CMAKE_PREFIX_PATH and fill in the path the cmake directory.

cmake_env

And now, let’s append the user path variable. Edit this bad boy, and hit new to append our path to the bin folder.

path

Sweet azz. Now let’s keep moving, it’s already making me sleepy. In the root of the usd_houdini_plugins folder, which for me is: W:\dev\toolkit\usd_houdini_plugins\
make a folder called “build.” Now In here is a “CMakeLists.txt” file. The default output is to dump everything into C:\Users\YourName\Documents\houdini17.0\ and this is shit. It will be dumped in with everything else, and be hard to fish out. If you don’t care about this, ignore the below custom output location set up. But for those who want to keep it out of there, see below!

Here’s the Vanilla, let’s delete stuff. Remove all the if >>> down to endif, and set your path to where you want to output the data.

cmakedefault

Below is what I’ve cleaned it up to. It’s where all my houdini/pipeline tools live.

cmake_custom

And here is the append line to make the DSO go to your custom locale. Just add the INSTDIR pathto\\where you added in above\\dso in the line below, and you’re gold.

cmake_dso

Here is my CMakeLists.txt
Okey dokey, with that done, open a command prompt and CD to the build folder we made earlier. Now your prompt is at W:\dev\toolkit\usd_houdini_plugins\build> (obviously your location is different!) let’s do some hacking.

run: cmake -G “Visual Studio 15 2017 Win64” ../  and wait for the magic. Here’s a boring gif of the process for sheer entertainment.

cmake

Amazing. I feel like Neo, I’m sure a pill offering is on the near horizon for me. Hop inside the build folder and you can see all our hard work. Double click the following: “usd_houdini_plugins.sln” this will launch Visual Studio, all ready to rock n roll.

All we need to do is select the “install” and go and change from “debug” to “release” then right click “install” and “build”

vs

Once it’s all done, you’ll get some sexy confirmation messages in the output window. If it all went to plan, there will be all the USD Plugins in the location you chose earlier.

usd_output.JPG

Sweeeeeeeeeeeeeeeeeet! Now add this to your houdini.env file:                          HOUDINI_PATH = “W:/Pipeline/Houdini_USD;&”

We made it Wendell! I hope you managed to stay awake for this. I didn’t. Here’s a zipped up binary built against 17.0.459 for you lazy bastards Houdini USD Plugins

usd_plugssop

 

 

 

 

 

 

I’ve been having a serious look at using spheres and also boxes to represent the collision
shape in bullet simulations. Spheres are great in that you can rely on the geometry to not get caught and hang on to each other. Boxes offer a nicer settling motion in certain setups too. The main reason I wanted to look at it, was to avoid always needing to use glue constraints. Sometimes I want a nice quick voronoi fracture that uses the clustering option, and this yields shitty collision approximations with convex hulls.

Enter vdb sphere packing! It allows me to fill the wacky geometry shapes and use those as colliders. I just save out my points, and transform the original pieces. Voila!

vdb_sphere_packing

Tinkering with using uniform or varying volume, along with reflection and refraction to create more interesting attenuation of light.

vol_ref