black polygons !?


#1

well,

every now and then during the process of modelling some polygons turn black. what’s wrong with those ?!

first i thought that their normals might have been reversed, but that’s not the case. :shrug:

in this example i appended the polygon into a hole on the surface.

anyone know why that is ?!


#2

It happens sometimes that way, when you used the append to polygon tool, you moved it clockwise to make the polys. You need to go counterclockwise. To fix this, just select the black polys, and go to edit polygons/normal/reverse. When you have two sided lighting turned off you will see all poly normals that are reversed.


#3

like i said, reversing normals doesn’t help … when switching on ‘custom polygon display->faces normals’ the normals of black polygons point outward from inside the mesh, like all the other non-black polys do. dunno what’s wrong. :shrug:


#4

yep, i know this problem , i think its due to the vertex normals.
an easy way to fix this is to convert the whole thing to subdees and back to polys again (level 0) … this cleans the mesh in most cases.

hope it helps . .

Flo


#5

I dont see why you would have to switch the actual geometry. I suggest trying to delete and redraw the faces, in the CCW direction, and see if that takes care of it. As for your problem, its a new one for me then. I’ve never heard of that happening.


#6

This has happened to me many times too. I just converted to sub d’s and then back again. I know its a pain, but its just one of maya’s tricks to piss us off!


#7

I’ve had this happen to me with my other video card, Gforce
plus it locked up all the time
check your card with the hardware compatability list see
if it mentions anything.
…does it render weird? or just display?
joe


#8

it could be a couple different things doing this…one…for some reason maya could have prelit the polygons making them black…i’d suggest do an apply color to the whole mesh with white and see if it fixes it… if that doesn’t do the trick…there are a couple steps in order to fix problems such as these…one is to unlock the normals… that is the first step… you do that by selecting the vertices…going to edit polygons, normals,set vertex normal, go to the check box…in the box click the unlock normals button…click normalize, then apply… if that fixes it, it might turn all the edges to hard…just do a soft/harden to fix it and get it back to the way it was… if that doesn’t fix it… try going to edit polygons, normals, set to face…you shouldn’t have to go to the check box on that one… that will make everything hard so you should have to do a soft/harden after…that really should fix your problems…if it doesn’t…check to make sure the vertices are welded together…and you do a conform on the whole mesh…you could also do a cleanup on the mesh to fix any nonmonifold geometry…that could cause a similar problem as well… hope this helps…


#9

yeah, ‘unlocking normals’ fixed that issue ! :bounce:

i just had to smooth out the surrounding edges again and everything was ok … thanks a lot, ppl !

btw, ‘yes’ it also rendered black polys black … :frowning:


#10

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.