Re: Single Prim Complex Objects

From here, particularily Kelly's response, such complex "single prim" shapes could be possible with CSG. Albeit no longer primitive, the complex shape would be an amalgamation of prims either adding or subtracting away prims. The link in my signature covers a lot of posts and feature requests which basically ask for this, and my letter to Philip even comes with tutorial links on how to do it. ^.^

YES! CSG would indeed be a great and virtually bandwidth free enhancement that would make SL modelling MUCH, MUCH more interesting.

But before that I'd like to see true hierarchical linking.

Thanks for the links.

Does CSG end up trading one complexity for another? Ie., reduced polygons helps the GPU, but do we increase CPU utilization to perform the boolean operations? My concern is SL seems CPU-bound, not GPU-bound.

Or can the CSG calculations be done only "once", when the object is first constructed?

Thanks again,

-peekay

Given the complexity would be on the same scale as solving the "Alpha Z order sorting problem" by slicing alpha faces where they intersect…

The next thing we are likely to see is the ability to set the polygon count on cylinders and spheres. This would give us more shapes.

One thing to remember is that all prims (ignoring trees) are extrusions of a base pattern. A Sphere is a circle that is stretched and then shrunk along a sine wave path.

Given this it would actually be possible to make a primitive prim mesh where you could specify the base pattern using a list of offsets from the center and then the list of extrusion path points.

Even being able to lock a flexi to a specific arc would be nice.

From thread: Philip Town Hall Transcript (5/18/06)
/3/6b/108906/1.html

[...]

By the way, there was a caller or I think a typer on the last Town Hall that had asked a question about CSG and our support for CSG - Constructive Solid Geometry. She sent me a follow-up piece of email that spoke to what the question really was, which was, 'When are we going to do subtraction and union and the other Boolean operations that you can do?' What this means is if you take, what it would be great to be able to do in Second Life would be to be able to take a primitive, intersect it with another primitive, then use that primitive as a subtractor, meaning it kind of carves out the other primitive where the second primitive was intersected with it. That is something that makes a lot of sense, and I think you'll see us looking into if we can do that in the future. We know we'd like to do it. Second Life's system is not at all inconsistent with being able to do that. So, I appreciate the follow-up I got there. It is something that we're taking a look at, and I apologize for not understanding the question better last time we all got together. So, let's keep goin'.

[...]

One of the reasons they don't like it is if you take a sphere and intersect it 99.99% of the way with a sphere of the same size and subtract #1 from #2. You get a very difficult to render surface.