-- Knifing Polygons -- Back to tutorial index

Overview: I will show you how to cut up your polygons...to generally destroy your mesh! fun fun

Step 1: Lets start with a cube, make it editable (press c) and go into the polygon tool mode.

Step 2: Now we will select the knife tool. In R8: right click in the viewport and select the knife tool. In XL7: STRUCTURE > KNIFE. Now with the tool selected we can start cuttin that cube up.

Step 3: Below the object manager, you will see a tab called ACTIVE TOOL. This panel allows you to change the attributes or parameters of the specific tool in use. For the knife tool there are two settings. CONSTRAIN ANGLE and RESTRICT TO SELECTION. First we will cut up our cube, in the viewport click and drag the line thats visible is where the cut will be made.

This is how I made my cut, you will notice that the line went into the right face of the cube, this will triangulate the mesh...well this is easily fixed.

Step 4: With the selection tool select the 3 pieces

Step 5: In R8 you can now right click and go to the bottom to UNTRIANGULATE, and click ok. In XL7 go to STRUCTURE > UNTRIANGULATE.

In this particular example it is only untriangulating 2 of the faces.

Step 6: A couple other tricks, if you recall from above I had mentioned the parameters...one being constrain angle, this will allow you to make more precise cuts, as it snaps the knife tool in place for you. To do this, hold the Shift key while knifing, if you move the mouse around you will see that it snaps and makes cleaner lines. Another Tip: If you want to make a cut all the way around a object, press F5 to go into 4view mode, and make a straight cut on an alternate view, this is make a straight clean cut, either horizontally or vertically.

Questions? Mail me.

(This tutorial was only designed as a refference point with the tool, not to instruct you on becoming a master with it.)