Grimrock

I would like to make bone definition in model file becouse I had some problems with making new monster, but I dont understand function of InvResMatrix in bone definition.
IMHO it is important property for bones. I making some tool for managing modelfile (in Delphi) and this work so so for Add/set bones etc.

Can someone explain me what means vector in bone definition? (invRestMatrix)

As explained in the Model and Animation File Formats document, invRestMatrix is a 4x3 transformation matrix that transforms from the modeling pose (also called rest pose, t-pose etc.) to bone's local space. It's the inverse of bone's transformation matrix. These matrices are needed so that the rendering engine knows how the bone transformation in animations correlate to the modeling pose.