Simbiont:Fusion UVW Tutorial

Case Study

In this example we are showing how renders from a 3d software package can be used in conjunction with Simbiont:Fusion. I’ll only cover usage as diffuse color, but certainly other techniques can be employed. This example won’t be using any of the 3d tools in Fusion, only image sequences.

Ingredients

• Lighting Pass(es) – This is the scene without the textures applied. Mine is all grey but you could have colored lights, sub-surface scattering, or render one pass per light and mix them in post
• Matte Passes – These let you isolate an object or group of objects
• UVW pass(es) – This is the most important part. We’ll need a texture that converts position or UVW into RGB. The renders need to be unclamped float color, openEXR for example. In 3ds Max, use InfoTexture, to generate these passes. Make sure that there is no lighting in pass and the textures should be fully self-illumnated. In this tutorial I added two alternate UVW passes to demonstrate some different behaviors.
  • Sticky – Texture sticks to deforming Objects
  • Sliding – Texture Slides when Object Deforms
  • Reflection Vectors - Simulates spherical reflection mapping
• DarkTrees – These are the files that darktree uses. They consist of the components, like Fusion’s tools, wired up in a node tree, and the settings on all the parameters. Some of those parameters are exposed to the Simbiont called “tweaks.” This is similar to Fusion’s macros. The internals are hidden and only the important controls are exposed.

The composite is pretty straightforward. Copy the matte pass into the alpha of the UVW pass, and isolate area you want to apply the texture. Connect this to the UVW input on the Simbiont tool. At this stage you should see the texture conforming to the original object. Repeat this for all the objects in the scene. Then merge on the lighting pass with the mode set to multiply. At this point the composite is done. Try adjusting the tweaks in the simbionts and the scaling. Also experiment color correcting the lighting.

Results

And here all three versions. We plan on using more interesting models in our examples but tubes and spheres will have to do for now.

This is a close up of the tube with all three variations and with the UVW passes that generated them.

General Advice

Retexturing like most post effects only work on a single sample per pixel. This means that blending operations like anti-aliasing, transparency, reflections etc won’t work in a utility pass ( uvw, z-buffer, etc). Blending in color passes is valid but meaningless in a z-buffer pass. At the edge of an object one must not anti-alias. Combining a distance of 100m and 1m doesn’t mean the pixel really lay at 50m. They must be dealt with separately. This also includes motion blur and depth of field. So consider this technique with care.

The uvw pass should be 32 float and unclamped. Allow for negative values if possible. Remember we are converting position into RGB.

Experiment with manipulation of the uvw pass. Color correct or add noise. Swap the channels.

Tweak passes need be rendered from the 3D scene. Otherwise it will look like the camera is manipulating the texture.

FeedBack

Love feedback. Tell me what you think. I intend to do more tutorials, both for our own tools and also for existing software. So watch this blog.

Ben Lipman

DarkTree texture repository

Tweak Parameters

When a DT file is loaded, the parameters of the flow exposed for user manipulation (aka ‘tweaks’) are added as Fusion inputs. Implemented tweaks include the MAPPING, SAMPLING, BOOL, FLOAT, BUMP, INT, PERCENT, COLOR, and STRING types. The screenshot above shows several tweaks including color, percent and integer parameters for the fxBubbles texture.

Image-based Dynamic Tweaks

For tighter control over the adjustable parameters, images from the Fusion comp can be wired into the tool as dynamic tweaks. Percent, bump and color tweaks can be controlled on a pixel-by-pixel basis using this method. This feature allows for creative integration with existing compositing projects, and animation effects that combine the strengths of the two packages. The following effect was created by dynamically tweaking DT parameters with a simple grayscale animation (see the bottom of this post to download this the example comp “Dueling DarkTrees”).

UVW Mapping

With the UVW lookup channel, DT textures can be directly applied to 3D geometry in Fusion. The image on the right shows this procedure, where a render was produced in 3D Studio Max and exported with UVW texture coordinates encoded as RGB. The middle row is a lighting pass that was merged with the DT lookup output to produce the textured bottom row.

Examples

The following .zip files contain Fusion comps, texture files and media that you can use to learn about SimbiontFusion.

Dueling DarkTrees

Snowflake sprite generator

UVW lookup texturing

DOD/ROI example

Extra Usage Notes

… for Fusion users:

1. You must hit “Load” to reload the map. It’s a bit like the FBX loader, in that it stays cached.
2. Your inputs should probably be the size of your output. No scaling is done in the tool. If you use the mapping input, then that raster size is used.
3. Metadata is not implemented yet.
4. Frame format settings are not implemented yet. You must manually set the raster size.
5. Supersampling is not implemented yet. If you need finer sampling, try working with a larger raster size and scaling it down afterward.
6. Motion blur is not implemented yet.
7. Image input and wireless links are a bit “odd” when you duplicate/instance the tool.
8. Otherwise, just think of it as FN but way cooler.

… for Darktree users:

1. Values are normalized for Fusion use. So a 0-100 tweak in Darktree will be 0-1 in Fusion.

We hope you enjoy the plugin… drop us a comment if you find it useful. Bug reports and feature requests are also welcome!

For those of you who haven’t heard of Darktree, it’s a powerful procedural texture authoring and rendering system, but it has a node-based compositing interface that’s similar in appearance and function to Fusion, just with a completely different toolset. For those of you who haven’t heard of Fusion, it’s the thing that makes the Sun so toasty.

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