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View Full Version : RFM artefacts, slow renders, etc..


bonsai_kittenz
08-22-2006, 04:05 PM
hi all,

a few prbs, hopefully i'm coherent enough...beginner-ish, so please bare with...using RFM 1.0, maya 7.0. this is a setup i have no control over...

first off,

noticing that on simple geometry, when using displacements, sometimes getting white dots that flicker randomly on the surface. they're usually a few pixels in width, and only last a frame. they aren't th displacement going over their bounds, as far as i know.

second prb,

have a very simple scene with a cube instanced onto a grid particle system. particles are only simply affected, by gravity and turbulence. the cube has the default lambert shader. using a directional light, no shadows. - so here's the problem, it's a sequence of about 1800 frames, and i'm noticing that render times are growing almost double each frame, until they grow from a start time of 30 seconds, to a steady rate of 25 minutes per frame. render globals are pretty much set to default, ray tracing and mblur are off. this even happens when rendering a test frame twice. first one clocks at 30 seconds, the next, exact same frame, takes 1.16 minutes. kinda lost on this one...

third prob,

almost a lot like the first one, i'm using geometry that has been mucked with a fair bit, but is still simple. when i say mucked with, i mean created something, then would go back and edit history so that the object would look very jagged and funky. history is deleted afterwards, and i have a shader that uses a displacement, and also a simulated metal with a reflected value going through a samplerinfo node to an env node ball. anyhow, what i'm getting is that closeup the surface is completely getting screwed up, almost looking like a hatched surface. when rendering at a distance, seems normal.

i'm very gracious for any help that can be provided, i can divulge more if need be. thnx!

twedzel
08-22-2006, 07:29 PM
The instancing is a known bug with RFM, I am not sure if they have fixed it in v1.2.

The artifacts that are happening on a displaced mesh, are you raytracing the mesh?

if so select the mesh, in the Attribute editor go to attribute > Renderman Attributes > Manage attributes... and add a trace displacement attribute to your mesh. This will tell RFM to add displacements into raytracing calculations.

bonsai_kittenz
08-23-2006, 08:15 PM
hey there, thanks for the speedy response..

that's cool about the instancing...at least i know now. i can live with it mostly.

as for the displaced mesh, i tried to trace it, and still nothing... it looks as if some of the normals are screwing up, but im sure they're all clean...

again, thanks for any help

The instancing is a known bug with RFM, I am not sure if they have fixed it in v1.2.

The artifacts that are happening on a displaced mesh, are you raytracing the mesh?

if so select the mesh, in the Attribute editor go to attribute > Renderman Attributes > Manage attributes... and add a trace displacement attribute to your mesh. This will tell RFM to add displacements into raytracing calculations.

ChristopherP
08-23-2006, 09:07 PM
For the displacement-artifacts...also try increasing the value for the displacement bound.


Chris

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