Mantra micropolygon VS raytracing VS PBR, which is faster ?

[jeffz]

In mantra render,

Micropolygon, Ray tracing and Physically Based Rendering (PBR), which one is faster ?

What is the limitation ?

( My need : still image, different materials, no motion blur, no fur)

Thanks.

[cwalrus]

bump

[toadstorm]

PBR and raytracing are more or less the same thing... if you crack open any of the default shaders, you're going to see the Compute Lighting VOP in there, which is running pbrlighting.vfl internally. The main difference you'd notice as a user is that if you're trying to run PBR-specific shading nodes with the raytrace engine, it'll likely crap out, and if you're trying to use some more old-school tricks in PBR, you might get unexpected results. Most of the time I use the raytrace engine and make sure my materials are all using Compute Lighting at some point, and this seems to work well for most scenes.

Micropolygon is an older approach that's really great in a few specific situations, but it has limitations. It's best used with volumes, especially with displaced volumes, since it can crank through them very very fast. IIRC you have to use deep shadow maps on your lights, however, and if your shader requires raymarching (i.e. multiplying density against volumetric textures) you're not really going to see any speed gains. It doesn't seem to work properly in IPR mode, so if you want to see the actual speed gains you'd expect on volumes, render to MPlay. If you're doing volume-heavy work and you don't need fancy lighting, it's worth a shot to see if you can make it work, but it's not as easy or predictable as raytrace/PBR.

90% of the time you'll be using raytrace/PBR.

[cwalrus]

Hey. I know you.