Yes, you can use setAditionalColor, but, the method is mostly used for give an ilumination to an object so the resultant color will be very bright. This question was answered few time ago. In anyway, have a look to the model3d program on the download section. I use it to set the color of my objects. Have a look to the resultant color and check if its what you need (unzip it at a path with non spaces like C:\whatever\).