How to 'cut' a polygon using the mouse?

i would like to render a scene whereby i can cut the object using the mouse…

for e.g an apple in half with the knife

SYNTAX ERROR

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ERROR CODE 321

To complex expression.

here are some hints:
read about CSG (contructive solid geometry), boolean operations. the stencil buffer can also be used to do this, read some general information about it. it’s mostly used as an example for using stencil buffers.
BSP’s and the assosiated algorithms are also very usefull. good luck.

hull, don’t you read the thread-topics ? you should!