3D Plane with Texture problems in Unity...

I am using the 3D Modeler Cheetah 3D and I get some issues. When I cut the plane to make it look like something else it when I apply the texture it gets skewed and look bad. The only time the texture is correct is when the plane is a box. The problem is I don't want it to be a box shaped plane. I want it to be differently shaped and the texture still works...

Does this problem has to do with unity 3D or cheetah (modeler)?

You probably need to UV map whatever shape you're making. If you don't know how to UV map in Cheeta, google it. Regular two-triangle planes don't typically need to be UV-mapped, since they're square.