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strange artifacts on a rendered image: stripes

Posted: Fri Jul 18, 2008 9:00 am
by giacob
look at the bottom left

Image


it is the first time it happen to me... ( it is not e cooperative render)

Posted: Fri Jul 18, 2008 10:22 am
by tom

Posted: Fri Jul 18, 2008 10:28 am
by giacob
i used single face as emitter.... i render this scene before and that didnt happened

Posted: Fri Jul 18, 2008 10:36 am
by tom
If you have the scene always causing this at the moment, feel free to send it to me. ;)

Posted: Sat Jul 19, 2008 3:20 pm
by av
Hi Tom

I've been having the same problem after 1.7

After several tests it seems that the problem occurs (it's most noticeable) when a emitter (single face 2d surface) has a high number of edges.

To solve this problem this emitters need to be triangulated.


As an example I've made this simple test scene in formZ with just a 3D enclosure for the "room" (default mxm) and four 2d surfaces (emitters), a rectangle, a 12 edge surface, a 36 edge surface (circle) and a 128 edge surface (circle), all with jomaga's sodium high pressure 1000w mxm applied.

Image Image


The only diference between the two scenes is that the emitters are triangulated.

Top view of the emitters:
Image Image



This test renderings are all sl8 (with multilight), directly from formZ 6.5.6 (plugin 1.7.0.4) to mxcl 1.7.0.1 in a macpro with osX 10.5.3

paulo

Posted: Sat Jul 19, 2008 9:53 pm
by Bubbaloo
No pictures are showing from that last post...

Edit: Now they are. :oops:

Good tests. Seems this is a very important step.

Posted: Sun Jul 20, 2008 1:24 am
by av
Alternate links for the images from my previous post

Single face emitters
Image

Triangulated emitters
Image

Wireframe Top view of emitters (single face)
Image

Wireframe Top view of emitters triangulated
Image

thanks Bubbaloo

paulo

Posted: Sun Jul 20, 2008 7:07 am
by tom
av wrote:After several tests it seems that the problem occurs (it's most noticeable) when a emitter (single face 2d surface) has a high number of edges.
Yes, I've said the same above ;)

Posted: Mon Aug 18, 2008 10:52 pm
by flycast
What does triangulated mean? How does one triangulate a flat plane emmiter imported from Maxwell's primitives in studio?

Posted: Mon Aug 18, 2008 11:27 pm
by -Adrian
Triangulation divides polygons, until everything is made of triangles. That's what all render engines work with, even the OpenGL view in your 3d app.

If you use a polygon modeler there's definitely a triangulation feature in it. If you export to Maxwell from a Nurbs app, this should be done automatically. Afaik only MoI can export Nurbs to quad polys.

Posted: Mon Aug 18, 2008 11:32 pm
by flycast
Thanks for the explanation Adrian. So the question still remains...How do I triangulate using Maxwell studio when I have imported primitives plane from their set of primitives?

Posted: Tue Aug 19, 2008 7:51 am
by pwrdesign
I dont know if I've missed something in this thread, but you should NOT have your emitters triangulated like that, thats what causing the errors in your render.


Regards Patrik