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How do people make low prim count mesh stuff?

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   Well, i have never tried a building physic but i fixed the physic of one part of a building with the mesh in Pic.1. It is set as convex hull. i can move around/inside it without any obstacle. It just has alittle hovering (Pic.2) but i noticed lots of buildings have it.

   The second i want to say...Isn't it hard to make a mesh with proper looking, proper LOD for 1,000 m. and low LI, especially if it includes rounded geometries. Even it is set to 2,000 m. as default at Mid Graphic Settings.

   As the last, to exclude lowest LoD, is one dimention of 10 m. enough or do all 3 dimentions have to be 10 m. at least ?

 

Screenshot_8.png.4b9088300172769bffe4cb3b0a882100.png

Screenshot_9.png.22c4d2a7fd441fd8357d3370de7cc0d8.png

Edited by Memo Opaque

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The mesh in your picture will work when set to convex hull if each of the boxes is a separate object (a linkset). So each box will just have it's own single convex hull, hence it works correctly. If it is a single mesh, a single convex hull will encompass the entire mesh, when set to convex hull. That's the default physics shape the importer assigns to any mesh uploaded, even if you don't specify a custom physics mesh at all. When set to Prim, it's using the custom physics mesh, either as a triangle based mesh (not analized), or the specified mesh decomposed into a set of convex hulls (analized).

For the LI calc, and the dimensions, it's the radius of the bounding box of the mesh. The formula to calculate the radius is this:

r = Sqrt(X*X + Y*Y + Z*Z) / 2

And the radius that determines which LOD is dropped out of the land impact calculation is this:

Lowest dropped at r > 5.43 m
Low dropped at r > 10.86 m
Medium dropped at r > 43,44 m

So if the BB radius is more than 10.86 m, only the Medium LOD will have an effect in reducing the download weight of the mesh. You can load "Use Lod above" (the medium LOD in this case) in the Low and Lowest slot as well, without increasing the land impact.

 

Edited by arton Rotaru
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i used 6 prims for it inworld and linked them. Then i saved the linkset to my desktop and reuploaded it as single mesh. And thank you for the detailed explanation about radius. So from the formula you shared, i can see it calculates radius as half of 3 dimentional diagonal of a rectangular prism.

Edited by Memo Opaque

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19 hours ago, Memo Opaque said:

It just has alittle hovering (Pic.2) but i noticed lots of buildings have it.

Yes, you can't avoid that if you use hull physics (that is if you get the uplaoder to analyze the physics). All serious mesh hosue makers are aware of that though and the solution is usually simple: don't use analyzed phsyics for walkable surfaces.

 

19 hours ago, Memo Opaque said:

The second i want to say...Isn't it hard to make a mesh with proper looking, proper LOD for 1,000 m. and low LI, especially if it includes rounded geometries. Even it is set to 2,000 m. as default at Mid Graphic Settings.

Tell all the LoD butchers out there! There are so many meshes in SL that requires you to lag down you viewer by increasing the LoD factor to 2 and even to 4 - and there are even meshes that won't work with the LoD factor maxed out. If you know how to make mesh, there is so little to gain and so much to loose by skimping on the LoD models.

We've been discussing this many times before and I know my view isn't a particularly popular one but stick to it: What you make for your own enjoyment and use is nobody's business but yours. But if you are planning to sell your builds, make sure they work with RenderColumeLODFactor set to 1. Because if you can't do that, you're not good enough a mesh maker to charge money for your works.

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