Hi

I have a problem with half of mine character. half of mine characters polygons is pointing inwards.

So when i take it into a engine i can't se half ofthe character, and i can see the whole the other side for the inside.

How do i change the direction of the polygons?

many thx Robin!

Try a reverse sop on the backfacing Geometry. you might also try deleting the point normals with a Point Sop and seeing if that's where you're problem lies when rendering.

if some of your polygons are oriented correctly and some are wrong and they are all part of connected mesh
you can try Facet SOP/Orient Polygons
it should make them all oriented the same way, then you can use Reverse SOP if you want the other way

i tried Facet sop/Orient polygons and Reverse SOP but i don't work. when i take Facet SOP at my OBJ nothing happed, and when i i take reverse SOP the right sdes polygons change and go outwards. but the left sides polygons go inwards. Reverse SOP did what you said but Facet SOP did nothing.

does it matter if i have cimbinded some OBJ togather or should it make the same result?

Perhaps try a clean sop -> orient polygons and follow it with a reverse if you need to. Then a facet to compute your normals.

it worked kind of. but still not. now the body and the head don't have the same polygon direction. the whole face a pointing inwards and the body outwards.

is it some other way to do it?

they really don't want to have the same direction :twisted:

Place a Facet SOP, and check
Pre-compute Normals, Orient Polygons, Post-Compute Normals

I suppose you'll want the two sides fused into one mesh (if they're not already), so you might as well choose Consolidate: Consolidate Points Fast.

Dragos

PS The help card for the Facet SOP has some useful info.

when i take the facet SOP and put Orient Polygons on, the body turns out right but face don't. and when i turn on Consolidate Points Fast nothing happend.

Pre-compute Normals and post-Compute Normals did do anything.

it's always some part that works with facet SOP and some parts of the character that don't.

Can you post the model / hip file?

Dragos

i can't do that the model is for a private person who does not want it shown to anyone.

Let me explain a bit more about the model to give you a cleare view:

First of i made the characters left side fully completed and then i mirrored it after that i added some more detail features and finally i combined it all into one mesh/object.

I have a idea that i can go back in my save files to the stage before i combined it and change it there (not a very large work a round a fully managalbe)
Or do you see that as a possibility?

Kind regards
Robin

Did you use the mirror SOP to combine them?
I still think the model can be fixed at this stage, but without seeing it it's hard to tell. Are there any internal faces maybe?

Dragos

What do you mean with internal faces?

yeah i used morrir SOP and combinded everything so i could use my autorig.

The Mirror SOP by default also reverses the primitives so the primitive normals are properly handled. You “should” have no issues.

Let's step back, wayyyy back to the beginning.

Are you actually looking at Primitive Normals or Point Normals? Are they Blue or wine red? Blue = Point Normals. Remember that SOPs preserve all geometric attributes in most all cases. This means that pre-formed Normals will keep their orientation after countless reverses or any other destructive operations. This is a very very good thing btw and is a core behaviour in SOPs.

You can't see the mirrored half. That screams to me a point Normal issue. Maya files import in to Houdini with point Normals present. Just append a Point SOP right after the File SOP and in the Normals parameter, choose the menu option “No Normals”. This removes the point normals. See if that works.

—-

One problem that arises from character Models imported from Maya/Soft/Lightwave is bad data. I frequently find duplicated primitives and degenerate wing-edged polygons in many a Maya/Soft/Lightwave model. These degenerate polygons don't play nicely with many operators.

Another issue with orienting polys is unshared points. If you want to use the Facet > Orient Polygons technique, you have to ensure that points are shared and that there are no degenerate polygons in order for it to work reliably.

One way to detect degenerate polygons is to use the Measure SOP and measure by area. Degenerate polys generally have zero area or very very small areas so you can identify them that way. I don't know if the Clean SOP does that.

Yes i am looking at the primitive normals im sure.

when i take on (no normal) in the parameter in the point SOP, should i a differense at the obj then? I don't see any differense.

and the same problem come. Every thing have the right direction at all primitive normals exept for the head and the left hand.

I did know some thing about the measure SOP so thx alot. I could use that one.

i remade the problem with 2 simple obj. so you can have a better look. i made my character at the same why with the mirror and so on.

when i tried a clean SOP at this new obj. everything worked out but when i tried at my character it diden't.