12/21/2023 0 Comments Houdini renderman tutorialBecause all the samples sharing a material are essentially running the same little program, SIMD structures the machine code so that a given operation (single instruction) can be run across lots of points at once (multiple data). For a render engine like renderman or mantra to run efficiently, it has to be able to shade many samples simultaneously. It's worth pressing this point an acronym that get thrown around for SL and VOPs (and it's underlying language VEX) is SIMD: 'Single Instruction Multiple Data'. The only difference being that rather than operating on geometry points, its operating on micropolys, or shading points. Further, because the geometry networks (VOPs) and shading networks (SHOPs) are so similar, you can often just copy paste your network over, and hey presto, its a shader. Poly shapes, nurbs curves, particles, voxels, it doesn't matter. If you're outside the network, it doesn't try to recompile, and is fast fast fast.īecause of the core behavior of Houdini that 'everything is points', it means you can design a VOP network and use it on just about anything. Under the hood it uses its own compiler (vcc) to compile stuff to fast multithreaded machine code on the fly when you're within a VOP network it recompiles each time you make a change to the network, which might incur a 0.1 second delay as it compiles. Unlike python, it's multithreaded, unlike C++ it's easy to learn. Vops, like XSI's ICE, is visual programming environment. Futher, whatever work you do is specific to this context (pushing verts around), it can't be easily transferred to other geometry types or other domains of maya. The problem is that using python or particles won't be multithreaded, so you'll hit performance bottlenecks quickly, and a plugin, unless carefully written, won't be hugely versatile. Convert to soft body, write a per particle expression.Everyone expects it to be there, and everyone is surprised when they find it doesn't exist. In maya, a classic case that comes up all the time is a noise deformer (ie, move every vertex on a mesh by a procedural noise function). Vops are a wrapper around Vex, which is similar to RSL, which if you know either of those acronyms you shouldn't be reading this beginners guide.Vops are like expresso in C4D, but better (I think, never really used it).Vops are like XSI's ICE, but more general in scope.Vops are a visual programming interface.Vops are a node based way to create create fast multithreaded plugins.Vops are a node based shading network, but as well as describing surfaces, they can also deform, create and destroy geometry.I'll tell you the point, it's Vops.īut what are vops? Why are vops? A few glib one liners depending on your background: You might have dabbled in Houdini before, followed some tutorials, and thought 'ok, interesting, but whats the point?'. 2 Noise that always increases with cellnoise vop.
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