Scene files

Attached is an example file for rendering a scene using ambient occlusion in combination with the -u option on the mantra output node to create an ambient occlusion texture map.

This can be useful for multiplying with texture maps on geometry that takes a long time to render like buildings and landscapes where you can get away with doing it a single time rather than for every frame. It can also be extremely useful for adding depth to texture maps on fur, though you would want to do an image sequence as opposed to just a single still.

All nodes in the file are commented to help with readability.

How it works:

* The output drivers use the unwrapping parameters. These allow you to specify an object (and vertex attribute to use).

* Each object has a vertex uv texture attribute. The texture attribute must be a vertex attribute, and fit in the (0-1) space.

* The geometry which is used for rendering must be made of polygons. However, the map can be applied to any geometry after that.

* There is a custom shader enclosed in the file. This shader doesn't use frontface() to orient normals. Instead, it only shades one side of the geometry. This is so that the front/back faces of the geometry will be shaded consistently.

* You will notice that there are seams when texturing. If you examine the texture map, you'll see that the uv coordinates do not quite map around the full object. When MIP Maps are created by the texturing engines, these black edges are blended in at the edge of the maps. You can improve the quality by expanding edges of the map. This is reason that we pass our textures to compositing rops immediately after creation.

* Also, the maps can be post-processed. For example, you might decide to blur the map, or run the map through a despeckle filter, or paint it by hand.

This is a Python SOP that rounds the corners of an input planar geometry. The selected points of the first primitive get filleted, and the result is accurate inscribed circular fillets (as from machining; Polybevel gives different results). The DA also "unfillets" (solves for the original corner of a rounded corner). The DA is embedded in the hip file. The python code is commented with references to math source.

This dynamic simulation of a smoke bomb integrates Houdini's Rigid Body and Voxel Fluid Dynamics. The smoke is emitted using information from the bomb canister to make sure that it emits in the desired direction while the canister spins through the air. The look of the smoke is derived from the material-based noise which sticks to the smoke as it moves. The final look is also enhanced with per-voxel motion blur.

One interesting thing to note in this simulation, that was not used in the video released on the main page, is the creation of an extra "color" volume which can be used to emit color in the smoke. Both videos are included in the attached file. This should help provide incite into how the volume tools work in Houdini.

Note that there is commenting on all nodes found in the file, and that some values have been changed from the video that was posted earlier, and this attached file to provide a more responsive experience. These changes will be made apparent in the commenting.

How it works:

* An rigid body simulation takes place causing the canister to fall and spin.

* We use the orientation of the canister to control the initial velocity of the fluid smoke

* Takes are used in this file for easy render passes.

* One thing that is important to note, is that lights that are lighting volumes must have motion blurred shadows turned off to correctly render motion blurred volumes.

This file contains a series of dynamic simulations to illustrate how one may perform some simple particle fluid work, and have voxel fluid fire spread from one object to another. The fire works in a way where two fire objects share a single smoke container and so are able to share temperature information so that one object can ignite the other.

This file has been slightly altered from the one appearing in the gallery to help the user simulate at a faster pace. Note however that there is extensive commenting on all of the nodes found within the file, and that these changes are reflected in the commenting so that they can easily be set back to higher quality levels.

How it works:

* A voxel fire simulation spreads fire from one object to another.

* The fuel attributes were painted onto the box geometry in a way that allows the fuel to burn up.

* A secondary, independent simulation drops particle fluid liquids onto the box to emulate the look of a fuel.

* A tertiary, independent simulation ignites flames on the ground in a painted area.

* Takes are used in this file for easy render passes.

* One thing that is important to note, is that lights that are lighting volumes must have motion blurred shadows turned off to correctly render motion blurred volumes.

This file contains the SOP network for creating a teapot.