how can i convert a matlab plot in 3d to a binary image?

I use trisurf for plotting a convex hull i need to convert it to binary image for using "Geometric measures in 2D/3D images" for calculating minkowski functionals but i don't know how to convert

[Image Analyst]

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[sarvenaz babakhani]

i searched alot but i dont know how to convert plot in 3d to 3d binary image