DAD opened this issue on Nov 12, 2002 ยท 18 posts
DAD posted Tue, 12 November 2002 at 7:53 PM
I created a terrain in Bryce and exported as an OBJ but when I bring the OBJ into Poser for texturing some of the UV mapping coodinates are reversed so that the textures do not show when the object is rendered. Is there a way to fix the coordinates so that they all face in the same direction for rendering?
BeatYourSoul posted Tue, 12 November 2002 at 8:15 PM
AFAIK, there are no normal reversing tools in Poser. You can do two things: check and fix them in Bryce or get UVMapper (www.uvmapper.com) and fix the .obj file with it. You have to be careful about exporting .obj's in some programs. For instance, Cinema 4D creates reversed normals when exporting .obj, therefore it is necessary for me to either reverse them in C4D before export or fix them in UVMapper prior to importing into Poser. BeatYourSoul
DAD posted Tue, 12 November 2002 at 8:41 PM
I've got UVMApper ... it can't fix this. These are random reversals as not all the UV coordinates are pointing in the same direction. I have even tried importing the OBJ into another program first and exporting without UV coordinates so that UVMapper can create new coordinates ... same results. Some are pointing inward, some are point out.
BeatYourSoul posted Tue, 12 November 2002 at 9:16 PM
I don't understand what you are talking about. :) Open the OBJ in UVMapper, select the facets you want to invert, and select "Tools->Facets->Invert". It will only invert the selected facets. I've just done it to prove it. BeatYourSoul
EricofSD posted Tue, 12 November 2002 at 9:52 PM
Attached Link: http://www.xdsoft.com/explorer/
Here's a thought. Run it through 3dexploration. I've found that to work wonders on fixing mesh issues like reversed normals, etc. Just open and resave.DAD posted Tue, 12 November 2002 at 10:21 PM
Will try 3DExploration and see what happens. Thanks for th help.
Lyrra posted Wed, 13 November 2002 at 5:28 AM
I've had objects with just a few flipped facets and used Uvmapper Pro to fix it with no trouble. Perhaps its only the pro version?
BeatYourSoul posted Wed, 13 November 2002 at 9:36 AM
I was thinking the same thing, since that's what I'm using as well. Hey, whatever get's the job done. BeatYourSoul
DAD posted Wed, 13 November 2002 at 11:57 AM
It is the Pro version only ... and 3DXploration doesn;t work either. Can't afford MapperPro right now. Guess I'm screwed for the time being. Oh Well, thanks anyways.
ScottA posted Wed, 13 November 2002 at 12:30 PM
No you're not: 1.)Export the model from Bryce in .DXF file format. 2.)import the model into Poser 3.)export the model in .obj format 4.)open the .obj file in UVMapper(free version) and let it create a new UV map for it. 5.)save the new updated .obj in UVmapper That will fix it. .DXF format strips out all the normals info. Every last drop of it. So when you re-create them by exporting from Poser in .obj format. They all face the same way. I invented this little trick several years ago for the RayDream users. ScottA
RHaseltine posted Wed, 13 November 2002 at 1:22 PM
You can also select the facets with the grouping tool in Poser and then select "reverse normals" from its control palette.
DAD posted Wed, 13 November 2002 at 1:45 PM
Selecting Poser only works if the normals are totally reversed and you're seeing holes in the model where there should be solids. What is happening here is the model is importing as a solid object (no reversed normals) but the UV coordinates are pointing inward on some surface planes and outward on others so that when the texture is mapped it only appears on some of the model. The areas where the UV coordinates point inward are flat blank color planes. ScottA I'll try your suggestions but I've had problems with DXF's in the past doing this too after I convert them in Poser. Maybe it's just me, but I've always had UV mapping coordinates get f&*ked up like this and it has forced me to dump a lot of good looking models and abandon them because of it.
ScottA posted Wed, 13 November 2002 at 2:09 PM
You can also do it the way RHaseltine suggests But you have to do it this way: 1.)Select the individual inverted polygons wth the group tool. Then assign them to a new group 2.)Once you do that. You can select that new group and THEN hit the "reverse Nomals" option in the grouping pallet. 3.)You can export the model from there to fix it permanently. And re-arrange the grouping to your likeing with UVmapper. There's several way to go about fixing this kind of thing. Whatever one you like is the best one to use. But it is doable. ScottA
thgeisel posted Wed, 13 November 2002 at 2:23 PM
I have the same troubles with plants modelled in xfrog. The curios is, only the leaves are wrong. tried uvmapper pro and anything i can think of ,without no good results.
DAD posted Wed, 13 November 2002 at 3:24 PM
BeatYourSoul posted Wed, 13 November 2002 at 4:24 PM
UV coordinates can not "point in the wrong direction" (easily, anyway). Each UV point is directly correlated to a model vertex point. So, a point of a facet of a model with UV coordinates has both X,Y,Z and U,V coordinates. If the model points and UV points are in different directions with respect to each other (one clockwise, the other counterclockwise), than, to put it nicely, you're screwed. I have no idea how you could even get this to occur without physically editing the file (or using some strange settings for export). There is no easy way to fix this without first deleting the UV coordinates and recreating them from scratch, as far as I am aware. Normals are values that denote a perpendicular direction to a surface, like a facet polygon, or vertex by way of its parent facets and tell 3D apps which side of the facet is front facing. Most of the time, they are just calculated by the orientation of the facet (clockwise or not), but they can also be specifically stored (as in .obj files - vertex/vnormal/vtexture for each point of the facet). And, normals work on both the model vertices and UV coordinates by default. If you invert the normal of a facet, you invert the side of the facet onto which the texture is placed (and thereby seen). You are correct that facets with inverted normals (or not ordered properly) in Poser are displayed as holes in the model. I can't really suggest much for this except maybe re-exporting it with different settings after a thorough inspection of the model or loading it into UVMapper, saving the model without any normals or UV coordinates, reloading it and creating new UV coordinates. BeatYourSoul
ScottA posted Wed, 13 November 2002 at 4:38 PM
From the image posted. It looks more like a mesh structure problem than a UV problem. ScottA
BeatYourSoul posted Wed, 13 November 2002 at 6:17 PM
ScottA, that is totally possible. Could be overlapping polygons on the mesh. That could cause problems all over the place. If one set is facing one way and another the other way, but the texture is only being applied to one, there would be no "holes", but irregularities in texturing. As I said, careful, thorough inspection of the model sounds like a very good course of action. BeatYourSoul