CompuServe Messages

Here are a couple of unrelated questions that popped up while I was working on something recently. 1) I rotated a fairly large plane I was using to make some clouds and the got a "world octree is too large" error message when I tried to render. Rotating the plane back took care of the problem, as did selecting everything in the scene and scaling down. but I don't know what the world octree size even is. I know more or less about octree levels (which I have set to the max in preferences) but world octree size is a mystery. Any one willing to enlighten me? 2) Has anyone else found that the defocussing in Imagine's DOF is pretty abrupt? Trying to get some depth of field into an outdoor scene with a receding pattern in the ground, I found a definite line where things went out of focus almost at once. I think I am doing the DOF setup right. I am using the actual camera y size to set the depth of field because this is the only method I can comprehend. Is this causing my abrupt defocussing? Michael