UV Mapping in Maya

First of all remember that in Maya the drop down menus at the top change depending on which menu set you are in. For UV mapping you want to be in "polygon" mode. In the default layout the option for this will be found directly underneath the "file" menu.

The texture we'll use to help unfold the uv map.

Now there are generally two approaches to laying out UV islands.

  1. Planar project the entire object.
  2. Select and cut all seams at once.
  3. Unfold entire object.
  4. Optimize, Resize, and Pack all islands.

Alternately...

  1. Select faces of an island and for that island...
    • Add cuts to island (if needed, the outer edge of the selection does not need to be cut).
    • Auto project the selection.
    • Unfold selection.
  2. Repeat making the islands for the entire mesh.
  3. Optimize, Resize, and Pack all islands.

Which approach you use is really up to you. Some people enjoy envisioning the final product all at once and dividing the mesh into pieces via selecting edges. Some enjoy doing it by selecting groups of faces and concentrating on one area at a time. In reality, for complex models, you'll probably end up using a combination of the two.

Creating UV Maps (Quick way)

In either approach you're going to start with a set of polygons to run a projection on to start with. This is so that we ensure the polygons are connected to start with.

Let's approach this one step at a time. Step one. Use 3DS Max for texturing.

  1. Select your polygons while in the "face" component mode.

    If selecting one island at a time then rememeber to try and choose groups that look like they could unfold to lay flat easily.
  2. Next we run a projection command select "Planar Mapping" from the drop down menu (under "create UVs").


    The selection should reposition in the UV Editor window.

    If selecting one island at a time then using a projection command like this will automatically cut your selection from the rest of the model. This means the only cuts you'll need to add at this time are for seperating pieces that wrap around (cylindrical shapes) or for helping curved pieces to lay flat. Do steps 3 through 6 for each island.
  3. Switch to edge component mode and select all the edges that need to be cut (see the general Texture mapping section for info about deciding where seams like this should go).
  4. From within the UV Editor window choose "Polygons > Cut UV Edges". Nothing will immediately change.
  5. Switch to UV mode by holding control, right clicking and selecting "UV".
  6. Apply "unfold" either by the dropdown menu under "Polygon" or by the "Unfold selected UVs" button. Note: If this is the first island on the project to have unfold applied to it then you may want to set one of the default options of "unfold".
    • Within the UV Editor window go to "Polygons > Unfold > Options (the square symbol next to the word "unfold")".
    • Uncheck "Pack". This option makes the program want to pack ALL of your islands when you only want to unfold one island.
    • Click "Apply" or "Apply and close".
  7. The piece(s) should be unfolded and visibly separated along any cuts you've added. Move the island(s) of the newly mapped piece out of the UV bounds and away from one another so that they do not overlap (for our own benefit).
  8. Within the UV Editor window use "Polygons > Optimize" to relax the islands. Unless you want to keep a straight edge you can probably select all of the islands when doing this.

    (Note that as of the 2015 version of Maya "relax" has been replaced with "optimize". They essentially do the same thing.)
  9. Enable "Display checkered tiles" in the UV Editor toolbar to see a checkerboard shader applied on your model.
  10. Scale the islands one at a time so that they have a similar amount of detail (similar sizes of the checkerboard on each part). More important areas (faces) should of course be given slightly more detail (evident by smaller squares of the checkerboard).
  11. At this point it's just a matter of moving, scaling, and rotating the islands to get them into a good packing.

Splitting edges / seams

Maya does not have designated "seam" objects and uses selected edges to split uvs apart.

Splitting polygon groups by an edge or edges is as simple as selected "Cut UV Edges" from the "Polygon" drop down menu within the UV Editing window.

PLEASE NOTE: You MUST be in edge mode for this to work properly. If you use "Cut UV Edges" while in face mode then all edges that make up the selected faces will create cuts!

(You can also use the scissors icon in the UV Editing window toolbar.)

What if you want to store edge selections for future use?

Maya uses "selection sets". It is as simple as making the selection you want with the sub tool of your choise and then invoking "Create > Sets > Set" from the dropdown menu. It will make the set as a new object that can be found in the Outliner with the individual component parts listed as children. Right-clicking the new object and choosing "select set members" will select the previously selected components.

A few more points that might help...

  • "Select all" in maya is not just "CTRL-A", which brings up the attribute panel, it's "CTRL-SHFT-A". Furthermore, by default, "deselect all" has to be chosen from the edit menu.
  • Holding down the Control button before bringing up the right-click menu will bring up a conversion menu between sub object types.
  • If the "unfold" command does not seem to be giving you good results, such as is the case when using the default setings on the top half of a sphere (pictured), then you may need to adjust its settings. Either right-click on the command or select the square icon next to the command in the drop down menu to access those options. Push the "weight solver" towards slider all the way to the right and try again.
  • While selecting components, if you've already boned the object, you may need to switch to a component selection mode instead of using the default right-click-to-select approach. Use either the "select by component type" button at the top or the F9 through F12 keys to select points, edges, faces, or uv faces to prevent yourself from accidentally selecting other objects like joints or ik handles.
  • You can also define islands by selected edges but you can't just move that group within the UV editor and have it automatically seperate from the rest. You must first click the "seperate uvs along selected edges" button to create a new island of your selected faces and move those with the Move UV Shell tool.

Creating UV Maps (Old instructions)

Once we have the checkerboard texture on our model we can close the hypsershader and open the UV texture editor. Do this either by going through "edit uvs > uv texture editor" in the file menu or clicking the far right icon in the polygon shelf. This and the planar and camera mapping options under "Create UVs" will be our main tools.

It will be tempting to use the "Automatic Mapping" function found under the "Create UVs" menu. ONLY do this to create islands. It will not make reliable "complete" maps. Unless you are working with something as simple as as a cube you will get oddly shaped uv maps cut in ways that will make seams evident, textures a pain to draw, and islands that are harder to fit together in your editor.

One other helpful thing to recognize is the "display image on/off" button. This will hide the texture in the window if you have trouble spotting the polygons.

Now that things are set up we can start the actual process.

  1. Use the "Move UV Shell" tool (which moves entire islands at once) to move ALL polygons in the uv Editor out of the main UV canvas into the grey area.
  2. In face component mode, select the faces you want to be part of a single island. Make sure the island looks like it could "lay flat" in the real world if seperated.
  3. Under the "Create UVs" menu in the main window select "planar mapping" to seperate the selected UVs from the rest of the model.
  4. Under the "Polygons" menu in the UV editor, select "unfold". The selected faces should now be laid out.
  5. Examine the checkerboard pattern in the main window. If it looks too distorted then you may need to choose a different set of faces for the island so that the surface can flatten more effeciently. If only one or two vertices are creating distortion, it may be possible to use the normal move tool in vertex component mode to move their position within the UV editor for less distortion.
  6. If you're happy with the checkerboard, then move the faces within the UV editor off to the side to make room for the next island, it doesn't matter where (just be careful about putting them over other islands so that you can select it easily).
  7. Repeat until all polygons on a model are part of an island.
  8. Choose the "Move UV Shell" tool and use a combination of the move, scale and rotate options to pack the islands back into the texture as if you were trying to solve a jigsaw puzzle. Don't be afraid to move an island back out if another will fit better. Take your time with this step.

Older versions of Maya may not have the checkerboard view option within the UV editor. If they do not you'll have to make a custom texture to preview your UV map alignment / density.

Creating a procedural checkerboard

If you have a pre-existing file the first step is to open the hypershader. Open up the hypershader by going to Window > Rendering Editors > Hypershade. The easiest way to use it might be to select the "texture" tab in the upper right and then drag and drop your texture from another window into the texture tab area. While you have your object selected hold right click on the new texture and select "assign texture's material to selection".

To make your own checkerboard patter within Maya then you still start by opening up the hypershader. Either select the default lambert material in the "material" tab or create a new one (Create > Materials > Lambert in the hypershade menu) and select it. Choose "checkerboard" from the middle column (from the 2D texture category). Hold right click on the checkerboard in the work area and assign it to the material. You can then hold right click on the material (within the "material" tab, not the "work area" tab, and select "assign material to selection" (make sure the "textured" icon is depressed in the 3d view option bar).