Bending a 3D rectangle

Does anyone know how to bend a 3D rectangle so that it doesn’t have a sharp bend ??? and also to cut off a piece of the rectangle. Thanks.

Does anyone know how to bend a 3D rectangle so that it doesn’t have a sharp bend ??? and also to cut off a piece of the rectangle.
Can you be clearer exactly what you mean. Bend ? bend how ? What triangle ? 3D rectangle ? Do you mean a cube ?
Show an image of what you have and what you want.

Simple Deform modifier set to bend ? http://wiki.blender.org/index.php/Doc:2.6/Manual/Modifiers/Deform/Simple_Deform
http://cgcookie.com/blender/2011/03/07/tip-using-the-simple-deform-modifier/

What kind of a bend are you hoping to achieve? Were you wanting something where you were wanting it to gradually follow a curve, or is this a situation where you are trying to get something like a mitered corner? If you wanted a situation where it would bend along a path or curve, you would subdivide in editmode a few times to add vertices, and then you would draw a curve and add a curve modifier to that rectangle that you want to bend using that curve object as your guide. Now, if you wanted to do a mitered corner, you would select the end of your object that you want to modify, and you would use the command “shear”, and then it would create that mitered end. A shear with a value of 1 would give you a 45 degree angled miter.