View Full Version : Wierd PolyGons showing

08-10-2005, 01:30 PM
I have a model of a logo and when I render it it looks funky - I dont know how to explain so I will show you - please help!


08-10-2005, 02:20 PM
Looks like it could be smoothing errors on the flat polys. There are many more hightech solutiuons for this than I am going to give you now. There have been threads on this, someone will point you that way for sure, but until then the old school and simple way to deal with it for a logo is to just select all of the logo face (flat) polygons and give them a different surface. Copy and paste the surface over from the other logo surface (curved edges only now) in the surface editor but turn off smoothing for the new surface of flat polygons.

Sometimes you can adjust the smoothing angle but this is a for sure way to just get rid of it.

Edit: Looking at the pic again you might want to also use your judgement on some of those side polys as well. Some of them are pretty flat.

08-10-2005, 03:20 PM
It could be that you have duplicate geometry occupying the same space aswell. This will display simular artifacts (rendering alittle bit of each since it can't quite determine which is on top of the other). I'd pull one letter into a separate layer and examine more closely.

08-10-2005, 08:42 PM
Make sure you don't have any non-planar polygons.

08-11-2005, 08:07 AM
thank you all for your help = how do I check if I have non planar polys? Ads what are they anyway?

08-11-2005, 01:48 PM
It's noty likely in this situaltion that there are nonplanar plolys as you probably just extruded or used the text tool. Non Planar polys come in situations where you start pulling the points around on a ploygon with more then 3 points. A polygon has to always be "flat" that is, imagine a piece of glass - anything that is stiff and won't bend - no matter which way you rotate it it will still be flat within itself or remain "planar" flat like a plane. If you look close at a ball that you make witht the ball tool you sill see that all of the poly's are flat that make up the ball.

If you select one of the polys and hit the i key it will pull up the polygon info window. You will see that the flatness level is 0.

Now if you take the drag tool and pull one of the points out of the ball. Hit w for pollygons statistics and you will see that there are 4 non-planar polygons. (4 non-flat polygons). These are the flour polygons connected to that one point. Select one and look at the info panel again and you will find a number above 0 for the flatness level.

Polygons that are not flat do not render correctly. A tiange (3 point poly) by nature is always flat.

A last resort for handling non planar polys is to use the triplpe command - turning the quads into tris. In subpatch mode where points are pulled all over the place they are converted at render time into triangles.

In the ulikely event that your face polys became non planar on your logo you would do this:

Select one point of the face polygons.

Pull up the point info stats panel

Highlight the number in the Z data field Right click and select copy to copy the nuber of the z position.

Select all of the points or polys of the face polygons and hit v, highlight the z data afeild and right click to paste the number into it and click oK. This will place all of those points on the same z plane - assuming the logo is facing this axis of course.

08-11-2005, 03:50 PM
This screen shot looks like a smoothing error - I've seen it many times. What I do in order to keep the edges smooth and the front faces flat, is select the front faces and use the bevel too to give them a very small inset with no shift value. The smoothing between two planar polygons equals out to a perfect mirror reflection, instead of a slightly curved reflection caused by two polys that are at even the slightest angle to each other.

Or you could turn your smoothing angle way down, but then you might lose the smoothing on the edges.

You could also do the different surfaces suggestion mentioned above. That will work too without adding geometry.

08-12-2005, 05:29 AM
I've found a sweet spot of 40 degrees for the smoothing angle works for things like this.