View Full Version : Renderman "Cannot conform motion samples" error.

12 December 2009, 10:46 AM
Hello over there folks. ive downloaded the demo of Renderman in the pixar's website. and ive been trying to render some tearing nCloth on it with motion blur.. but the cloth wont render and Maya gives me this message:

"rfm Error: R07006 Cannot conform motion samples"

even if i bake the Ncloth Cache into the vertesis it wont render with motion blur.

so, whats the deal over here?

12 December 2009, 12:22 PM
anyone? i trully want to learn it without the need of buying it first.

12 December 2009, 01:12 PM
Not sure what that could mean , It might be that the Rib exporter screws up somewhere.
Could you maybe upload one of the rib files (prefferred) (if they are not to big ) , or just the section in the rib between "MotionBegin" and "MotionEnd".

On another note , you can try 3Delight for free (with their first license free policy) ,- great renderer !

12 December 2009, 08:18 PM
I have seen this error when rendering realflow meshes in RFM.

I think it basically means the topology is arbituary so the motion
blur can't work it out.

I can't really remember how to fix it. You may want to try
changing the way the motion blur calculates. ie. open, closed
or centre.

You could also try using subframe motion blur instead.

Like I say I can't remember exactly how to fix it though.

Hope this helps a bit.

12 December 2009, 02:29 AM
i've tryed it all.. open, close.. center... frame.. only changes in wich frames it wont work.

what should i dooooooooooo.

12 December 2009, 07:10 AM
I have seen this error when rendering realflow meshes in RFM.

I think it basically means the topology is arbituary so the motion
blur can't work it out.


You are right art_3d... with motionblur in renderman , the number of verticies has to stay the same at frame beginning and frame end to do deformation motionblur. So it makes sense that the motion samples error is spat out on tearing cloth , as the number of verticies will change. I'm quite new to this renderman thing , but I'll dig deeper and try to find a solution. If you find a fix PLEASE post it here , I'm very interressted in the solution.

12 December 2009, 09:07 AM
aaaaaa man!, mental ray can render it perfectly with motion blur.

so, what in earth should i do?

12 December 2009, 08:03 PM
It looks like there maybe a solution afterall.

I searched on the Pixar forum and this is what came up:

You have motionblur turned on, and the topology of the geometry is changing between frames. PRMan cannot motionblur if the geometry physically changes (number of cv's etc) over the course of the motion blur.

You can try the different motionblur options, like subframe, which may help in this. Also, you might search on motionblur or flow or similar in this forum, as I remember another posting where someone worked around it.

Basically the topology of the geometry must remain consistent from shutter begin to shutter end. I think that subframe motion may help when you have less than 360 camera blur, as the frame will be sampled at the actual points, rather than frame boundaries and then interpolated.

It helps to use subframe motion blur *and* shutter speed below 180.
The point is - motion blur evaluation should not evaluate the realflow mesh beyond 0.5 (half) frame intervals - that's the point in time where realflow meshes change their topology.

The workaround for more motion blur than the 180 shutter limit is to use the motion blur multiplier control on the realflow mesh loader node, if I remember correctly.

hope this helps

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