Hi everyone, I want to derive the transformation matrix to go from the model space of a child in a hierarchy to the modelspace of it's parent. I need help with the math for this. In more detail, I've got a hierarchy of objects in the scene. Each object has it's own position and rotation. I want to be able to set the position/rotation of an object in world space, and then compute the appropriate transforms for that object and all children of that object. //snip ascii art because I can't get it to display correctly.. I want to set the position/rotation of object A. These values are in world space. I want to calculate a transform that would take object A from model space to world space. Then I want to calculate transforms for all the child objects that would take them from their model space to the model space of their parent. I want to make sure that the interface (things like get and set_position) are in world space coordinates but that there are transforms for each object to the model space of it's parent. I hope that's clear and that someone can help me with the math to implement this. Thanks, neneboricua