I rebuild with curvature first for two reasons. First it lets me know the minimum number of CV's I could get away with to hold the shape so I have a good idea how many cv's I should use when I rebuild uniformly. Second, there was an annoying bug in Maya and as far as I know it is still there where you would rebuild a curve and it would go all wonky! For some reason rebuilding with curvature first seemed to fix it.
Rebuilding uniformly is important because it ensures that the parameterization (which is a complicated topic) but in simple terms it has to do with the way maya keeps track of cv's internally is normalized, which affect nearly all operations on curves and surfaces. So it is always a good idea to rebuild before using the tools. It is so important that it is one of the very few things I actually dedicate a hot key for. Both rebuild curve and surface.
Ah yes I thought I did a poor job of describing curve snapping. It goes by so fast hard to spit out all the steps before the video is over.
There are three kinds of snapping that I use alot -
Curve (c), grid (x) and vertex (v)
They all work the same.
1. You first select component(s) - verts, edges, faces...
2. then press and hold c for curve, x for grid, or v for vertex snapping (there are icons at the top of the gui for these as well
3. now if you select the y-handle of the move control all movement is constrained to the y-axis, if you select the other handles movement is constrained to their respective axis as well.
4. finally for curve snap, still holding the c key just press the middle mouse button while gesturing over any curve(edge) and all the selected components will snap to the y-value of a point at which you gesture over on that edge.
So in the video I used it to move all the verts on three of four edges to the same y-value of the curve I middle mouse clicked on.
If you hold the v key you press the middle mouse button while gesturing over a vertex
If you hold the x key you press the middle mouse button while gesturing over a grid line
THIS IS REALLY IMPORTANT and it's the reason this snapping is hard to describe. You cannot just middle mouse click on an edge you have to middle mouse click AND drag (what I call gesture) over the curve, grid, or vertex for it to work.
Two additional notes.
1. You don't have to first constrain the movement by pressing one of the move control handles. In this case all the selected components will snap directly to what you middle mouse gesture over. If you had vertices selected they would all stack to a single point (which is not very useful).
2. There are 2 options that can get you borked if you don't check it. In the move options (double click the move selection icon or press the left mouse button while holding the w key) and be sure "world" is checked (all this snapping stuff only works right in world mode) and the other box is "keep spacing" in most cases I have this box UNCHECKED. If checked the components move but keep their RELATIVE spacing.
One place grid (x) snapping is useful is when you want to move all the verts along the centerline of an object so their x coordinate is at zero. This is important when mirroring objects. You select all the verts, make sure move options is in "world" mode and the "keep spacing" box is UNCHECKED, press and hold the x key, then press the middle mouse button while gesturing over the origin [0,0,0] on the grid and all the verts will .... snap on top of each other to [0,0,0] ...
JUST CHECKING TO SEE IF YOU WERE PAYING ATTENTION....
You have to click the X-handle on the move manipulator to constraint all the points to only move along the x-axis, then press and hold x key, then middle mouse gesture over the [0 0 0] origin on the grid and all the verts will only move to 0 in their x-coordinate and will be aligned on the origin.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram : 17-12-2009 at 09:13 PM.