How to find the gap in the middle of the solid body

Some time while designing I forget to fill the material (small cavity) in the middle of the block and it will give a problem in manufacturing so how can I identify the gap.

By "gap" or "cavity", do you mean there is a narrow channel that is too small for the current tool, or there is a "void" in the part (like an air bubble) that you want to detect?

yes,the cavity may be small or it may be big in the middle of the big cast.In short to find a hidden gap in the cast element.

Before pursuing a custom coded application, I'd suggest that you ask around at the Siemens forums. There may be an option in the CAM application, molded part validation module, or a custom "check mate" routine already available to find these cavities.

yes,I will check