Creating Grass images with Alpha channel in Maya

Friday, June 6th, 2008 @ 4:44 pm | Tutorials/Tips

This tutorial is good for people who want to use a method of grass rendering that will not use to much render time and memory. We are going to create paint FX grass and then use that grass to convert it in to a 2d image. With this image we can populate the scene and render faster then rendering a forest sized grass landscape with paint FX.

This method is for front view and 30 degree angle cameras, consider this method as if its a matte painting technique.

This tutorial is made with Maya 2008 and Photoshop CS3. Any other program can be used.

1: Create a flat plane in your scene.

2: Make your plane paintable.

Drop down Menu Rendering > In your tools > Paint Effects > Make Paintable

3: Go to your visor.

Paint Effects > Get Brush.

4: Select the Bermuda Grass.

5: Paint a stroke on your plane.

6: Go to your front view port.

7: Change your scale rate in the attributes to your needs.

Also change any other settings to match your needs how the grass should look like

8: Render out your front view port.

9: Save your image as a PSD file.

10: Open up photoshop

11: Create a new layer.

12: Fill your new layer Black.

13: Duplicate your first grass layer.

14: Switch your black layer below the newly duplicated layer.

Now select the pixels on the duplicated layer.

15: Now fill that layer with white.

16: result of action filling the layer with white.

Now save your collor image and black and white image as jpg`s

17: Create a new plane in your frontview.

18: Create a blinn and two file nodes in your hypergraph.

19: Connect one file node to the blinn color.

Middle mouse the file node> drag over to the blinn node> release.

Then select color.

20: Do the same to the other file node but connect it now to your transparent channel.

21: Now add the color map to the color file and the black and white map to your transparent file The two.

23: Now apply the blinn node to your plane and render it out.

Now you can populated your scene with the image plane. Remember that depending on the angle of your camera you need to change the grass to correct your viewing angle, for example if you are going to render on top you will not be able to see anything, so before you create your scene, you need to know how you are going to setup your camera.