Step 8: UV Mapping
To setup the UVs I used "UV Layout 2". Select "Coca_Bottle" in the scene and export it as an obj. Load the obj file in "UV Layout 2" and layout the UVs as follows (Fig.31). I am not going to cover how to use UV layout in this tutorial, but if you are not familiar with it you can easily learn it by following the tutorials that's on their website. Here is the link: http://www.uvlayout.com/index.php?option=com_wrapper&Itemid=97
Once you are done with the UVs, export the model back into Maya. UV mapping the cap's treads can be easily done in Maya using simple planar maps. We apply a planar map to one tread and then we transfer its UV information to the rest of the 19 treads. This way all the UVs pile up exactly on top of each other (Fig.32).
Transfer UV maps
To transfer one object's UV map to another object, select the object that has the proper UV layout and then the second object with no proper UV layout and go to Mesh > Transfer Attribute Options. In this case, set the options as following (Fig.33).
Do this step for the rest of the 19 treads. Once you are done, all the UVs should pile perfectly up on top of each other. Merge all the treads to one object. Call the new object "Cap's Tread"
Step 9: Exporting "Coca_Bottle" UV to Photoshop for bump mapping
Select "Coca_Bottle", and then go to the UV Texture Editor. Once UTE pops up, go to Polygons > UV Snapshot. Set its options to those shown in Fig.34.
Step 10: Setting up a UV as a guide in Photoshop
Once the UV image is loaded in Photoshop, press "Ctrl+I" to invert the colors. Double click on the lock icon to pop up the new layer window. Call the new layer "UV_reference" and hit ok (Fig.35).
While the "UV Reference" layer is selected, change its style from "Normal" to "Multiply" so that you can see the layers underneath. Make a new layer under the "UV Reference" and call it "Bump" (Fig.36).