Normals in Amapi Pro 7.5 - Polyloop

Shonner · 27th December 2004, 00:56

I have a polygon sphere in Amapi Pro 7.5 with its normals pointing outward. I used the Symmetry Tool to duplicate the sphere. Its normals are still pointing outward, but only the inside of the sphere is displayed. It is the negative of the original sphere, but with its normals pointing outward still. I have to make the normals point inward for the sphere to look right.

Is this supposed to happen with the Symmetry Tool. Or should I only be using Copy/Paste to make more spheres?

Hugo · 27th December 2004, 22:18

Use duplicate and not copy/paste for copy your object.

Shonner · 28th December 2004, 00:05

What if I want a mirrored copy though. Like the other half of a face? When you hide backfaces, the mirrored half is messed up even though its normals are oriented correctly.

Hugo · 28th December 2004, 01:11

you talk about sphere, i awnser about that. A symetry of a sphere have no interest.
Copy and paste like says in the amapi box, it's not the best, you must use duplicate.

If you want to talk with a concrete exemple, say it before !

So for a face, use symetry tool

... and i don't see your problem.

whkguamusa · 28th December 2004, 02:20

Quote:

Originally Posted by Shonner

What if I want a mirrored copy though. Like the other half of a face? When you hide backfaces, the mirrored half is messed up even though its normals are oriented correctly.

I can see what you are talking about. Looks like something that needs to be fixed. Seems more like a display issue over a topology one.

In the mean time call up the "orient normals" tool on the copy, select all and use "unify normals" with the space bar to flip them until you can see them, with backfaces off, in the same view as the original object you duplicated them from.

wayne k
guam usa

Shonner · 28th December 2004, 03:55

I always thought that a polygon's backface always faces the opposite direction than its normal is pointing? Or is this not the rule?

I have objects that have their normals pointing outward, but so are their backfaces, too. Flipping their backfaces inward make the object visible, but their normals are pointing inward, too.

Anyway, I found a quick workaround in Amapi Pro 7.5 (which doesn't involve flipping normals) to fix object normals so that they point outward and their backfaces stay facing inward after making a mirror symmetry copy.

I used a sphere as an example to easily show the problem.

27th December 2004, 00:56	#1 (permalink)
Shonner Extrusion Join Date: Apr 2004 Posts: 190	Normals in Amapi Pro 7.5 I have a polygon sphere in Amapi Pro 7.5 with its normals pointing outward. I used the Symmetry Tool to duplicate the sphere. Its normals are still pointing outward, but only the inside of the sphere is displayed. It is the negative of the original sphere, but with its normals pointing outward still. I have to make the normals point inward for the sphere to look right. Is this supposed to happen with the Symmetry Tool. Or should I only be using Copy/Paste to make more spheres? __________________ Shonner

28th December 2004, 00:05	#3 (permalink)
Shonner Extrusion Join Date: Apr 2004 Posts: 190	What if I want a mirrored copy though. Like the other half of a face? When you hide backfaces, the mirrored half is messed up even though its normals are oriented correctly. __________________ Shonner

28th December 2004, 03:55	#6 (permalink)
Shonner Extrusion Join Date: Apr 2004 Posts: 190	I always thought that a polygon's backface always faces the opposite direction than its normal is pointing? Or is this not the rule? I have objects that have their normals pointing outward, but so are their backfaces, too. Flipping their backfaces inward make the object visible, but their normals are pointing inward, too. Anyway, I found a quick workaround in Amapi Pro 7.5 (which doesn't involve flipping normals) to fix object normals so that they point outward and their backfaces stay facing inward after making a mirror symmetry copy. I used a sphere as an example to easily show the problem. __________________ Shonner

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27th December 2004, 22:18	#2 (permalink)
Hugo Rhymes with Hell. Join Date: Jun 2003 Location: France Posts: 2,987	Use duplicate and not copy/paste for copy your object.

28th December 2004, 01:11	#4 (permalink)
Hugo Rhymes with Hell. Join Date: Jun 2003 Location: France Posts: 2,987	you talk about sphere, i awnser about that. A symetry of a sphere have no interest. Copy and paste like says in the amapi box, it's not the best, you must use duplicate. If you want to talk with a concrete exemple, say it before ! So for a face, use symetry tool ... and i don't see your problem.