Strange problems(Dissapearing Faces)!

I have the following prob:
I wrote a new back-end for my Q3-Viewer and everything works fine except for one thing…There are some faces that dissapear if one looks at them in a certain angle.
This happens only with some very few Faces(5-10) in an average Q3-level.
It doesn´t depend on the used texture…There are for example 10 faces with one texture and one of them starts dissapearing…
I didn´t change my front-end therefore it cannot be a fault in vis determination, but I really cannot imagine that this is a fault in my OpenGl code.
Did anyone have a similar problem with OpenGl?
Any ideas?

P.s.:I really don´t know what to do I debugged the code for 5 hours now and am not able to find the prob.If I swith back to my old back-end the problem isn´t there.

Thanx in advance, XBTC!

I don’t know if that may help but you’re not using the GL_EXT_cull_vertex extension with GL_CULL_VERTEX_EXT enabled or something ?

Thanx for the answer…But I disabled all culling already to make sure that that isn´t the problem…It happens if you look directly at the face and then change the camera orientation a little…

Plaese,please help me…I cannot see the debugger anymore…

Greets, XBTC!

[This message has been edited by XBCT (edited 10-04-2000).]

Could you put some screenshots of this.

Maybe this is simply caused by backface culling?
maybe somehow your normals are pointed in the wrong direction?

Thanx for replying…

>Could you put some screenshots of this.<

Don´t think that this would help much…You would see the floor of q3-dm1 looking identically as in q3 but with two missing faces…

>Maybe this is simply caused by backface culling?
maybe somehow your normals are pointed in the wrong direction?<

As I said befor I already disabled ALL culling so that cannot be the problem.And I only exchanged the backend with the new one
so my normal data, etc. cannot be wrong.

P.s.:Seems that it´s one of these problems which simply need to be solved in long hours of debugging…But if anyone has a idea please tell me.

Thanx in advance, XBTC!

Don´t think anymore…I solved the prob…
Greets, XBTC!