Z Taper

I have a cube that I would like to taper along the Z axis, but the controls only allow for X and Y axis taper. Is there any way to accomplish this? Can the definition of X, Y, and Z axis be changed for a cube? (If so, this would solve the problem).

Thanks

flip it over onto its side

When you taper by X and/or Y, you are shrinking or growing the top or bottom of the cube. Therefore, you ARE tapering "along the Z axis". I take it that's not what you meant though. A cube has 4 more sides in addition to the top & bottom, so I'm assuming you mean you want to shrink or grow one or more of those. What kind of shape are you trying to make?

If all you want to do is, say, shrink the "front" instead of the "top", you can of course just rotate the cube so that the top is where the front used to be, and that's all you need to do. If you're trying to make some other sort of shape, please say what it is so we can tell you how.

The reason I have the problem is that the X, Y and Z axis remain constant, even if you flip the shape on it's side. For example, if you hollow out a cube, it is done vertically through the Z axis. How would you do that through the X axis?

The same applies to the taper function. Turning the cube on side does not change the X, Y and Z definitions, only the orientation of the cube. The taper still does exactly the same thing regardless of orientation.

I want a cube hollowed out along the Z axis and tapered along the Z axis. This can not be done according to controls.

THe hollow is not always up and down though, if you rotate the prim it is side to side... not entirely sure what you want to do.. but seems like if you just rotate the cube you should be fine, as that rotates the axes (Though changing axis settings still remain the same)

It take it you meant you want it hollowed on a different axis from the one along which it is tapered, not along the same one. It's semantics, of course, but to me, tapering BY X and/or Y is the same thing as tapering ALONG Z.

Anyway, the reason the tapers and the hollows correspond with the Z axis (the polar axis) is because of the way prims are made. Each one is constructed by extruding a 2D profile shape along a perpendicularly oriented 2D path in 3D space. A cube, for example, is a rectangular profile extruded along a rectangular path. A cylinder is a rectangular profile extruded along a circular path. A sphere is an arc shaped profile extruded along a circular path. Etc., etc., etc.

Think of it kind of like what happens when you stand a coin on edge and spin it. As long as it's spinning, as it dances across the table, it appears to be a sphere. Stop the spinning though, and it's obviously just a circle. The spin in that example is somewhat analogous to the path.

The way "hollows" are made is by altering the profile shape so that the empty space in the middle of the path is exposed. This is why you can't have a hollow in line with the local X or Y axis, only with the Z. The path sits on the the XY plane. The change that, you'd have to fundamentally alter how prims are made, which would require a complete rewrite of the whole thing.

Tapering is also done by altering the shape of the profile. A fully tapered cube has a triangular profile, for example. In order to give the appearance of a taper that is in line with the XY plane instead of with the Z axis, you'd need to have the profile change size at every point along the path. That could get computationally expensive.




To answer your question, you've got two options. The first is to construct your shape out of multiple prims. If you're talking about the kind of shape I think you are, you'll need four tapered cubes to do it. That's what I'd recommend.

The other option would be to use a sculpty. Sculpties can be practically any shape you want. But the flexibility comes with a price. Each one has 2048 polygons in it. Compare that with a cube, which has just 108, and the difference is huge. Having a lot of sculpties on screen at once makes for a huge performance hit on most machines. Also, the physical shape of a sculpty is always the same as that of a torus, no matter what the visual shape is. So collisions with the object will never appear to correspond with what the object looks like.

Four cubes would be about 1/5 the amount of polygons of a sculpty, and the physics would be much more sensible.

Chosen,

Now I understand. Thank you. It must have been confusing with the references to "up and down" and Z axis.

Your explanation confirms to me that X, Y and Z axis designations never change in prims. You can hollow a cube through the Z axis vertically, turn the cube on its side and have the hollow be horizontal, but the DESIGNATION of the Z axis does not change. The Z axis has been rotated 90 degrees and is now horizontal.

This means that I can not hollow through the Z axis and taper along that same axis for the reasons you describe. I appreciate your explanation and your alternative building methods.

Thanks!