View Full Version : Lights and shadows

07-06-2004, 08:01 AM
I have some jpgs here of something I just rendered. Can anyone explain to me why I'm getting these render errors? The first image is lit with a spotlight with Ray Tracing turned on and the second uses a shadow map. I'm able to get the shadow mapped image alright by adjust the map angle, but could anyone help explain why this is happening and what I can do to fix or avoid these problems?

Thanks, I'm new.

07-06-2004, 08:02 AM
Shadow mapped file.

07-06-2004, 12:19 PM
Hard to say, but I would check for bad geometry. In Modeler, go to Polygon selection mode and hit w. Look for 2 point and non-planar polys.

Also, merge points, THEN do that first part...

07-06-2004, 09:01 PM
yea looks like you've got multiple layers of geometry. After Merging points ( 'm' ), Unify the polygons ( shift 'I'). This will get rid of the extra polygons.

07-06-2004, 09:11 PM
So I tried merging points and this is what I got. There were no non-planar vertices. It helped a little. Shadow maps are now fine but ray tracing still messes it up. I used the lathe tool to make it. Maybe I took it too far?

07-06-2004, 09:28 PM
Tried the shift I and it eliminated some 540 polygons but it did not affect the render. Maybe I just have to start over?

07-06-2004, 09:47 PM
Post your object to the forum and we can tell you what went wrong, it's better to know so you can avoid it in the future ~ it's almost certain that those black spots are shadows cast from doubled geometry.

07-07-2004, 11:11 PM
Thanks for the help. Here is my model.

07-08-2004, 10:33 AM
Your geometry is doubled, Unify polygons didn't work because one layer of the geometry is in subpatch mode.

Use the stats window ('w'), select either Faces or SubPatches by clicking the plus sign, and you'll see that they occupy the same space. You shouldn't need Subpatches for a model like this so I would delete those - it will render much faster too.

07-08-2004, 07:15 PM
Sweet it worked! Thanks for imparting your knowledge. These Lightwave forums are fantastic!

07-08-2004, 08:23 PM
You said I don't need subpatching for a model like this but I don't seem to have enough segments to really round off the round top and bottom of the cup. I was using subpatches to round everything off nice and neat. What should I do to round these off? I would have to Lathe more segments correct? Is that what I should have done in the first place?

07-09-2004, 08:32 PM
Yea more segments in the lathe. 96 should do nicely. Did you save a copy of the spline that you lathed?

07-09-2004, 08:37 PM
No spline but I could just deleted all the segments but one to use over correct?

07-10-2004, 11:47 AM
Use 1 row of the points (top to bottom) and create a 'profile' shaped polygon and lathe that.