View source for HowTo:FullUnwrap8Potato

=== "Starting Big" in Potato Mode ===

This may seem like a big contradiction, but I'll begin the work by using an automatic unwrapper: Archi's. Why? Because I've had the horrible experience before of apparently being finished with an unwrap, but some tiny polygon somewhere in the mesh is not yet unwrapped, by default unwraps across the entire UV screen, yet there's no simple way I know of to find where on the mesh it comes from. So, I'd rather start working from a fully unwrapped mesh, even if the quality of the unwrapping is for the birds...


http://deeplayer.com/wiki/tut/FullUV/blender_shot89.jpg


It also helps to have an automatic unwrap saved somewhere as a reference for relative sizes of islands. And to make the islands more easily identifiable, we'll do more than just save this automatically made layout, but we'll also bake a texture from it. Then, if you have a color printer, make a printout and keep it handy. Our real unwrap will look completely different from the above horror, but you never know what questions the printout might help answer at some time or other. But keep in mind that Archy does its own breakup of the mesh into UV islands; i.e.: It does NOT respect your marked seams.

If you're in doubt about the horribleness of the above layout, please refer back to the [[HowTo:FullUnwrap5Think|"Think Hard" chapter]], where I listed the requirements for a "good UV layout", --maybe print it out--, and then go point by point and see how the layout above meets, or fails to meet, those requirements. (Hint: there's only two requirements it meets, out of my list of 14...). Otherwise just trust me: You could never make a good texture based on that, and whateve texture you would make, it would take you forever, trying to figure out where things are in that rat's nest.

But okay, how did I do that? Simple: First divide your screen. Right-click on the the top or bottom edge of the window, click on Split. Then left-click on the split to move it. By default, you get the same view on both splits. This is good because, at laast myself, I like to have a split right in the middle of the screen, for UV unwrap work; and I can get the exact center by looking at the two images and moving the split line until they are cut identically (zoom in, make sure the same details appear at the edges of both images). Then you click on the bottom left icon of the right window and choose UV Texture Edit. Then change the left window from Object or Edit mode, to UV Face Select mode, and press A to select all facets.

The right window will show a total mess of vertices and be covered in overlapping facets, giving it a blue color. Just go to the UV menu there, top item, the Scripts, and pick ArchiMap, leaving everything at the default. Let it rip. May take an hour or two. Go for a Cafe Au Lait...


Done?

Okay, first save the file. Needless to say, I save my file often, with succeeding revision numbers. That way, if a corruption in the file creeps up that seems unrecoverable, I can go back to a previous revision number. This is a good time to save, because saving UV face layout sometimes causes Blender to crash and burn. Now go to UV menu -> Scripts -> Save UV Face Layout. Unselect SVG, make it look like...


http://deeplayer.com/wiki/tut/FullUV/blender_shot94.png


The purpose of this layout is NOT to serve as a layout. It's a long story; but Blender requires for an image to be loaded before you can bake stuff. What you may want to tweak is the Size. The size should be the size of the final textures for the ship. NOT the enlarged size you'll be working with during texturing. The size of the reduced finals. My standard is 512 for fighters and bombers, 1024 for corvettes to destroyers, 2048 for cruisers and carriers. For space stations I prefer to use multiple sub-objects with their own textures. This ship is a corvette, and therefore I set the size at 1024. (Note that, during texturing work (next tutorial) we'll be working at 4 times the final texture size: 4096, and we'll do all our xcf operations at that high rez, --only at the end to scale it back down to 1024.)

This will save for us a TGA --in my case called "Cutter17.tga"; you might want to open it in Gimp and save again as a .png, if you want to save disk space.

Now go to the Image menu -> Load Image, click on "Cutter17.png" or whatever the name is, and click Open. Congratulations! Now you're ready to bake.

Save the file again, and now go to the top menu, Render -> Bake Render Meshes -> Texture Only. Takes a few seconds. Then Image -> Save As... and give it a name. I just append "tex" to the default name. 


http://deeplayer.com/wiki/tut/FullUV/Cutter17tex.png


The colors in it are the diffuse colors you assigned your material. I don't know how to bake the specular colors yet...

Next, press F8 for the World panel. Make the Horizon and Zenith colors black. Make Ambient color 1.0 blue, 0.879 green, and 0.932 red. What's magical about these values? Happens to be the balance of RGB components for starlight; --at least in this region of the galaxy. Next panel on the right, Ambient Occlusion. Turn it on, put samples at 16, Dist = about the length of your ship, Add, Plain, Energy = 1.0, Bias = 0.5. Then go again to the top menu bar, Render -> Bake Render Meshes -> Ambient Occlusion, and go for dinner.

Ready? Image -> Save As... "Cutter17ao.png" (I'm just showing 512 versions here, but I AM getting 1024 textures, of course.


http://deeplayer.com/wiki/tut/FullUV/Cutter17ao.png


(to be continued)


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