Booleans- a mesh alternative?

[QuantumChaos Portal]

ive read alot of comments on these forums about meshes. what people hoped they would be theirs costs and prim upkeeps in the sl grid and how it went from a hopeful advancement to sculpties to just another accessory creation system for clothes and items worn on the body because of the prim counts these meshes produced vs sculpties were off the charts.

what if we had a simplified alternative for importing meshes.

a boolean in 3d modeling softwares have 3 states of being additive,subtractive,and intercecting. they rely on multiple objects primative or complex to create a mesh like structure.

if you had a sphere and a cube and placed the sphere inside the cube with 1/2 sticking out

if both objects were set to additive when grouped together their boolean state would look the same from the outside however the pieces that intercected would be gone and you would be left with a hollow mesh joining.

if 1 was additive and 1 subtractive then grouped the subtractive would cut itself out of the additive piece

you would either see a dipped bowl inside the cube or a sawed off 1/2 sphere depending on which 1 is subtrative

if they were both grouped together as intercecting then what remains is where they touch and nothing else which would be the bottom slice of that sphere.

so how would this be as good/better than meshes?

well by itself using nothing but prims if you didnt have the cash for sculpties or meshes it could open up a world of modeling techniques previously unobtainable in sl w/o outside software or expensive in world software.

but for those that have sculpty experience it could also provide alteratives to meshes because a sculpty is nothing more than a prim with sculpt texture therefore booleans could produce very detailed addative,subtractive,and intercecting combinations and if done smartly they would cost a fraction of the prim counts as mesh calculated prim worth.

the pricing for creating meshes this way could be just the cost of x number of prims used + sculpty costs=total cost of mesh created (if this is to simple of an equation for what it produces im sure the lindens could find a way to calculate it more to their liking w/o sacraficing the intentions of the system to reduce upload costs and reduce prim counts of mesh like structures.

 

obviously all of the above is not possible in sl currently however if people liked the idea of using booleans as the prim count to meshes it could produce rather effecient mesh alternatives if added to sl.

ie a mesh tree being worth 55 prims inworld might be created using 3 sculpties and booleaned together with an additive boolean calculation.

think about it.

 

[Coby Foden]

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QuantumChaos Portal wrote:

think about it.

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... starts thinking... :matte-motes-whistle: ... and wonders how could this possibly be any more efficient (with less vertices perhaps?) than the exactly alike object created outside SL? :matte-motes-sour:

[Drongle McMahon]

I think it is very unlikely for this or any other new modellling scheme, that they would apply the old prim accounting to it. They seem pretty determined that prim.land impact costs will reflect real resource consumption from now on. In that case, and automatic boolean mesh generator like this is unlikely to compete well with purpose made meshes. If it got close enough, perhaps the advantage of being entirely inworld and free of upload cost would make it viable.

[Josh Susanto]

If that happens, the next step is a button that applies fractal resolution enhancement to surface textures. 

[Helium Loon]

Boolean solid geometry is a WONDERFUL idea....but it will NOT work in SL.  Boolean operations on the meshes (even of internal 'prims') are very complex.  Doing that dynamically every frame while building would be horribly complex, not to mention slow the CPU to a crawl.

Boolean operations on meshes are fairly well-defined, so doing it as a single-click operation is doable.....but NOT really workable in SL.  The very idea of 'prims' is that the meshes are pre-defined.  Even though we can 'torture' them into funky shapes with twists, bends, and tapers, those are simple operations on the internal mesh of the prim, and do not actually change the structure of it.  Booleans will create NEW vertexes, edges, and faces when the operations are executed.....this changes the topology of the mesh, and its structure, creating a new mesh.  This would have to be downloaded from the server, just like existing meshes.

 

There are plenty of mesh editing programs that support boolean operations....create your 'prims' in there, do the boolean operations, then save it and upload it to SL.

 

[Drongle McMahon]

Still, it would be nice to exploit the mesh code to provide some enhanced prims to those who don't want to use external editing. I imagine some relatively meshes with unedtiable vertex definitions (like ordinary prims) but with the torturing parameter data slots used for other kinds of parametric midification, such as bevelling and eccentric hollowing. This should not require much more recalculation than do the present toturings or the recalculation of stretched sculpties. These would have initially to br provided in a system library. They would have to have land impacts calculated using the mesh system. Eventually it might be possible to let creators make them, with novel uses of the parameters, although I guess that would require huge additions to the internal mesh format, at least so that it could define vertex groups and the transformations to be applied to them when parameters change. Dealing with the UV maps might make this too hard?