Forum: Vue


Subject: UV mapping question

croxie opened this issue on Jan 16, 2008 · 28 posts


forester posted Thu, 17 January 2008 at 11:47 AM

Thank you for the links, croxie. This is an interesting grab bag of problems, and the short version of what I found will be that you are correct to "bin" these models. But not because models using a *.3ds file format are always suspect. Here's what I found....... It is good that you sent all these links, as one of the first problems encountered is in the model "packaging." That is, the maps for the speed boat (apparently the Roamer 43) are not included in the package for it, but instead are included in the package for the "yacht." So, one has to spill out all these models components into the same directory (file folder) before they can even begin to sort themselves out. (It must be that this is what you did to get as far as you have.) The second problem for these models lies in the fact that the model builder, Bireli Lagrene, is using the character set for a written language that is probably not installed on your machine, and isn't on mine, even though I do have the bi-directional character facility installed on mine. You probably noticed that some of the images files have names like "¤®áª¨ ¯¨àá .jpg." This is the operating system's way of telling you that it cannot interpret the character set being used. I opened up the *.3ds file format header of the speedboat and the first sailboat to read it (using a standard programmer's editor), and the headers calls for two each of the image files. But the characters appearing in the names of those files are different than those showing in the directory of image files. The operating system for our computers in not able to accurately read the character set in use, so it is fluctating in its use of characters, and therefore cannot associate the image files with the UV mapping coordinates called for throughout the *.3ds model file. Third, the yacht wants the image file for "Darfour_34_-152". I was able to determine that by looking at the model file's header file, reading it, and then applying that file manually to the model. (The model gets confused because of thoses multiple image maps being included in package, and the above mentioned character language problem). BUT, Mr. Lagrene apparently used a simple planar UV map to apply the texture to the model. Here's what he did - and here's the consequences of using this kind of mapping technique - see attached picture. (Sorry about the label in the picture - I do mean "planar" mapping.) And finally, the program used to make the model is creating curved surfaces with single-sided polygons. Without going into the technical problems of what happens when you use a cubic mapping technique to apply a texture file to a single-sided set of polygons, let us just say that this is why the boat hull map ends up getting applied to the sails, as well, in a particularly ugly fashion. OK, so this is a very good illustration of a model-builder using an inexpensive modelling tool (actually, probably AutoCad or one of its brethren, which is not thought of as being cheap), and taking a default UV mapping process in that program and applying it willy-nilly to the model. I bet this model looks great in his original program, and he just exported it into the *.3ds file format and called it "good." But it won't work for us. So, in the end, the reasons for your problem have little to do with the worthiness of the *.3ds file format, and a lot to do with some other kind of model-builder-made errors. Kind of a shame, because Mr. Langrene went to some trouble to construct this in the first place.