Object Too Far From Origin - some faces don't render

[gyster72]

I have an animated aerial scene - airplane flying above broken clouds with ground visible in openings of clouds. The spinner (center of the propeller) has some faces that do not render - the surface of the fuselage, which is underneath (behind) the spinner is visible, but it should be blocked by the spinner. I have read that this may be a problem when objects are too far from the origin, but in this case, I think the airplane has to be pretty far from the origin in order to be above clouds and ground. Also, the airplane is animated along a spline, so at some point, it is going to be moving away from the origin.

The spinner was modeled using a lathed spline, then converted to polys, and the normals are facing the correct direction.

If I move the plane to the origin, the spinner renders properly.

I think the system units are mm, and the plane is about 70m above origin.

I'm using 3ds Max 2012 and Vray 2.4 My system is a pair of Opteron 3170s with 40gb ram and a Quadro 2000 video card.

Does anyone know a work around?

Help is sincerely appreciated.

[tashko.zashev]

Could you try to increase the Secondary ray bias value to something like 0,002 and see if helps?

[gyster72]

Thanks for the response, but that didn't seem to have any affect. I currently have the spinner linked to the propeller, so it's spinning. I'm going to try and link it to the fuselage so it will not spin and see if that make a difference.

[duaxiong]

Try adjusting your Camera's near Clipping Plane to be further from the Camera.

[gyster72]

Thanks for the response. For now, I have modeled a "solid" spinner - the original has 3 openings where the propeller protrudes. I also added a shell modifier to it, and it doesn't rotate - I just linked it to the fuselage so it stays where it should on the rest of the model, and you probably won't be able to tell that it doesn't actually rotate. It's rendering frame 21 of 200 right now, and it is rendering all of the faces. After it's complete, I'll render a frame with the clipping plane nearer the camera just to see of that will also remedy the situation with the original spinner (the animated one with openings).

Thanks again!

[svetlozar.draganov]

If the issue still persists please send us the scene for investigation.
We won't need the complete scene, if you could isolate only the problematic area that would be great.

[gyster72]

Thank you Svetlozar. My wife says you are probably Bulgarian - is she correct? I am currently rendering the animation (frame 21 of 200 took 8 hours to render), so I will respond when it is complete - maybe October or so. So far, all faces are rendering properly with the spinner not rotating. When this is done, I will do a test render with the original geometry animated and adjust the clipping plane per suggestion below. If the faces fail to render, I will send the file after deleting the rest of the geometry.

Thanks again!
Guy Seela

[svetlozar.draganov]

Yep, she is correct Actually most of the people working at Chaos Group are Bulgarians.
Please send us the scene when the render is complete.

[gyster72]

I will send the file when it's finished rendering. I hope you all are not terribly affected by the conflict in Ukraine. Thanks again for the help and best wishes!


Guy

[m_hinks]

Had the same issue today, and had to go as high as 0.02 to get the faces correct. I was using geometry over 500,000 from 0, not by choice!

[svetlozar.draganov]

Would it be possible to send us some examples?
What parameter did you change to 0.02? Secondary Rays bias?

[m_hinks]

Hi,

Sorry missed your reply. I will try to make a test file, cant send the working file. I might have got away with a lower number, but jumped to 0.02 and worked first time! The setting is indeed Secondary Ray Bios.

Mark