Shading

Houdini

Rendering huge Houdini meshes in V-Ray.

I’m working on a production right now that involves sending absolutely enormous animated meshes (6.5 million polygons on average with a changing point count every frame) out of Houdini and into Maya for rendering. Normally it would be best to just render everything directly out of Houdini, but sometimes you don’t have as many Houdini licenses (or artists) as you’d like so you have to make do with what you have.

If the mesh were smaller, or at least not animated, I’d consider using the Alembic format since V-Ray can render it directly as a VRayProxy, but for a mesh this dense animating over a long sequence, the file sizes would be impossibly huge since Alembics can’t be output as sequences. Trying to load an 0.5 TB Alembic over a small file server between 20 machines trying to render the sequence and you can see why Alembic might not be ideal for this kind of situation.

Hit the jump below to see the solution.
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By toadstorm, ago
Maya

Ptex weirdness in VRay.

I’ve been messing around with using Ptex in VRay for Maya and ran into a particularly weird little problem involving a normal map exported from Mudbox. It’s probably easier to show it than to tell about it (Fig. 1): That wax wrapper looks terrible… not at all like the original Read more…

By toadstorm, ago
Maya

monster roll

A short film that I worked on with a friend of mine, director Dan Blank, is finally out to the public! I was the CG Supervisor, and I handled all of the lighting, materials and rendering in addition to the overall pipeline. Take a look at this article from The Read more…

By toadstorm, ago
Maya

applying displacement in vray

I was just talking to a colleague about his problems using displacement maps with VRay, and then remembered my confusion when I first tried to work with them. So here’s a post about it! Normally in Maya/mental ray, when you want to apply a displacement map you just create a Read more…

By toadstorm, ago
Maya

the “tech” shader

If you’re using mental ray as your renderer, chances are that you aren’t going to get a whole lot out of the passes system, especially if you’re trying to write custom color buffers. It’s a slow, buggy, work-intensive process to get a lot of passes out of mental ray that Vray has absolutely no trouble with. You could use render layers instead of custom passes, but mental ray also has a particularly long translation time for complex scenes (think of any scene where you see mental ray hang for about 10 minutes before it even starts to render a frame). So you can’t exactly add render layers haphazardly… you need to condense things as much as possible.

Someone told me about a neat trick that they saw at a studio they were freelancing at where three data channels would be written to RGB channels, almost like an RGB matte pass except with “technical” passes instead of mattes or beauty or whatever. Since the data being written only needs a single channel, you can get three kinds of data written to one image and then split them apart later in post. Simple enough when you think about it…

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By toadstorm, ago
Maya

Why your render layers break.

As promised, a useful post! And probably a long one.

As far as rendering goes, the problem that I see people running into more often than anything else is render layers mysteriously breaking, especially when file referencing is involved. The symptoms are typically either objects disappearing or Maya simply being unwilling to switch to a specific render layer, claiming in the Script Editor that there are “overrides to a node in a missing reference” or something to that effect. A lot of less experienced or just less technical types will try to solve the problem by either importing their references into the scene (which is rarely a good idea), or by screaming obscenities (which is exhilarating but ineffective). There is a better way to get your scene to render with no problems, and be able to use file referencing. The trick is to use shared render layers properly, only allow certain edits to your references in your final scene, and make sure that your references are clean.

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By toadstorm, ago