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View Full Version : UV Mapping bug in Layout



DaveWhitney
09-09-2006, 09:45 AM
OK, this is driving me batty. Here's a simple repro: In Modeler, create a sphere, and select 4 polygons near the north pole (not in contact with the north pole). Assign UVs. Note, we've assigned UVs for just these 4 polys, and not for anything else.

For the default texture, create a new image map, UV projection, pick an image file. Look at the object in Texture mode there in Modeller. It looks pretty much exactly like I'd expect it to: the image chosen fills in the 4 polys, nothing else outstanding about the object.

Now, load it into Layout. The first thing to notice is the texture view of it. Note the image is now smeared into adjacent polys! Now, render it. It's smeared in a different way! If you have LW9, change to the Perspective camera. Now the smearing is different still! If you have FPrime, render it there, and the smearing is different yet again!

In LW 9, at least, the problem does not occur with the perspective camera and if the containing surface for the selected polygons is flat (say, the center poly of a group of 9 making up the face of a cube). Classic camera still renders even that as crud.

DonS
09-09-2006, 03:16 PM
I'll be ****ed...I duplicated what you did and got the same result. Next, did the most obvious thing I could think of...namely, UV mapped the remaining polygons. Problem solved.

Seemingly, LightWave doesn't like a mixture of UV mapped and non-mapped geometry being assigned the same surface. Didn't try, but I'd guess the problem would also vanish if the other other polygons were assigned a different surface.

D.

toby
09-09-2006, 03:51 PM
I was thinking that might be it, other apps don't even let you apply uv's to just a part of an object, and weight maps are the same way. Simply assigning a 0 value to the remaining vertices fixes them.

gerry_g
09-09-2006, 05:10 PM
Agree with DonS, I regularly map things partially uv wise and yes the trick's to select the uv's name them in the requester, then invert the selection and name those too, but some other name obviously. Also you must set uv's edge to edge mode wise, not repeat or a flat color will carry over on to the rest of the geometry

DaveWhitney
09-09-2006, 05:46 PM
I was hoping to avoid the wasted resource consumption of assigning all the points a UV value. However, if that's the only workaround, so be it.

Now, to try it on my actual model...

gerry_g
09-09-2006, 06:10 PM
NO, only the four polys you want to uv map, the rest of the surface carries a conventional texture and does not need to be uv'd, sorry if I confused you, it just has to be named that's all.

DaveWhitney
09-09-2006, 07:08 PM
Well, I'm trying to put several images on the same surface at various locations. I don't want to break the surface up as that'll cause smoothing to break down. In fact, I'll be reducing the number of unique surfaces in order to improve the smoothing that's already present (as I'll have UV mapped all the images - I won't need so many distinct surfaces).

I could go with ordinary planar projection, but what I'm trying to do is rescue a model which has been oriented incorrectly (nose points down negative X, instead of positive Z). If I get all the various images UV mapped first, I can reorient pretty easily.

Some experimentation leads me to believe that the unassigned points actually get an assumed UV coord of 0,0, which is what leads to all the weird texture mapping. It would seem the only way out is to assign all points belonging to a surface proper UVs, which is a tremendous waste of space, as well as my time. grr.

toby
09-09-2006, 08:32 PM
What kind of break down do you mean? Smoothing works fine between different surfaces, as far as I know

gerry_g
09-10-2006, 05:39 AM
I think he believes it's necessary to cut or un weld the various parts of a surface in order for them to be i independent, where as mearly selecting and naming them as such is sufficient.