Billboard Image with transparency in Maya

1. Preparing Image in Photoshop

Obtain the highest quality source image. Proceed through these steps in order for the highest quality result.

1. In Photoshop Edit->Convert to Profile, set the profile to "SRGB IEC61966-2.1". Make sure the image mode is RGB and the bit depth is 8bits/Channel.

2. Edit the canvas size so the width equals the height. In the canvas size window - if you change the value to percent - this is very simple. Change it to 100 x 100 percent, 100 x 50 percent or 50 x 100 percent. This will make it easy to map onto a billboard of matching proportion in Maya.

3. Save a copy of the image as a psd file, and call it "ImageTitle_HResMasking.psd"

4. Use various selection techniques to make a selection of the part of the image you want to keep; then go to Select->Save Selection. In this dialog select that you want to create a new channel. (The alpha channel will eventually save-out with the .tif file and tell maya what parts of the image will be transparent, translucent and opaque.)

5. In the Channel palette - check that you have a new channel where white represents opaque, black transparent, and greys represent translucency.

6. Now, to avoid a fringe around the image, it is good to flatten the image with a color that is similar to the object that will be floating. Create a new layer behind the tree and paint a similar color - so the fringe in maya around the object will be the color you paint - not white or black.

One way to automate this process is to create a copy of the top layer - and put it beneath the original. Gaussian blur this layer with a setting of 2pixels, then duplicate it 3 times.

7. a general fill value behind everything that is in the middle range of the tones on your edges. Select everything but the "tree orignal" layer and merge them (command E or control E). Save at this stage.

8. After Saving, Resize the image. Go to image->image size. Set the Resolution to 72.  In most cases you will want the image to be less than 2048x2048 pixels. For 3D pixel dimensions of 16, 128, 512, 1024, 2048 are efficient.

To save RAM when rendering thousands of billboards in one scene - you will want these textures to be as small as possible, but larger than they will appear in the render so you maintain the resoultion of the original. So if your render size is 1280x720 pixels, and this tree is going to fill the frame, you would only need the height to be around 1024 pixels high.

9. Now your image, layers and channels should look like this.

10. Flatten the image.

11. File->Save As. Select tif for the filetype. (it is possible to use .iff and .psd for the filetype - but it is more complicated to build the shader network in Maya for some reason - so i recommend .tif because the shader network seems to streamline the process).

When you have your first image ready - proceed to Setting up a Billboard in Maya.
Joshua Mosley 2010