Softbodies error

Hello, I’m a beginner in Blender, I’m just learning. I made a box and a plane that falls over the box with the soft body property enabled.
But In the render you can see a mistake, some parts of the render are inside of the cube. I’ve included a screenshot in the post.
What can I do to fix it?
Thank you very much.

Attachments


Select the softbody object and move to Material buttons window(F5 key).
Then push Ztransp button on Mirror transp panel and increase Zoffs: value.

Thank you very much!!
It add a Zoffset for the material isn’t it?