FX PSD Blast Mark

New file ...

Fill with white, make new layer ...

Brush, spatter 59

Make a splat dead center

Scale it up

Radial blur ...

Select all and copy merged into a new alpha channel layer ... go Image Invert {Ctrl-I]

[If the image is not dark enough, you can duplicate the layer then make the alpha channel]

Scale the file down to 64x64

Save as file type TARGA

In max ...

Make a material ... load the file in the DIFFUSE slot ... set up like this ... the purpose is to avoid making a separate alpha channel file ...

Select Image Alpha

De-select Premultiplied Alpha for better edges

Mono channel output: Alpha

INSTANCE a copy of this to the opacity channel:

Apply map to a square plane and position on a wall. This is your decal.

Note: All lights: exclude decal planes from “cast shadows.”