Non-uniform scale causes rotation and deformation issues
3ds max Hierarchies Avoiding and correcting scale issues I'll scale up in the Z axis while watching the results here in the Transform Type In area so that I get a Z scaling of exactly 200%. Click and drag that up and when I get to 200 I'll stop and now that's been scaled up. We can investigate by going into the Transform Type In dialogue, right click on the Scale tool, and it says that I've got a value of 200.151. So I'll just round that off. Type that in and now we have a situation in which we have an object with non-uniform scaling. Now again, this is not a good situation. We're going to try to avoid this, but I first need to illustrate why we need to avoid it. So I'll close Transform Type In dialogue and create some links. Let's just link the head. Grab the Select and Link tool and link it to the chest. Then let's try rotating it. Grab the Rotate tool and rotate that head and instantly we see that there is a problem. The head is changing shape as it rotates.
In 3DS Max, is the scaling models bad and why? I'll undo that. I've actually got angle snaps turned on, so I'll turn that off and we can see the skewing happen interactively now. That's happening because of the order of operations for transforms of position, rotation, and scale. Similarly to how we saw that the order of rotation axes has an influence on the result, here we're seeing an artifact resulting from the internal order of operations of transforms in which objects are positioned then rotated and then scaled all relative to their parent. So that's the key to what's happening here. The parent object, which is the torso or chest, is scaled up by a factor of two. It's got a Z scale of 200 and what's happening is that is being inherited by the head object and it's happening after the rotations because the order of operations for transforms is, again, position, rotation, and scale. Okay, so that's why this is all happening. And this is happening because the scale is being performed after the rotation. Remember that the transform order is position, rotation, and scale. Alright, well we don't want to see this so let's undo. I'll right click on the Undo button, go into the History, and go back before we did the link. So select Link and choose Undo
