Decreasing poly count on models

Re: Decreasing poly count on models
Hi Y'all,

This topic may be of interest to LDraw viewers too since it's easy to get geometry bound.

This might be a silly idea, but for some parts you could calculate its axis aligned bounding box and then rendering an ortho view of the part (projected onto the bounding box) to a texture that becomes a normal map; then draw the bounding box with the normal map in-game. The idea is that you'd be "baking" studs, greebles and other small detail into a texture, which is something the game engine may be prepared to cope with.

(Commercial games use this technique in real production - you model a low polygon final object, then add 3-d detail, then 'bake' the 3-d detail back onto the low detail.)

One of the wins here is quality: when studs get very small you get a ton of aliasing due to tiny triangles - even 16x FSAA doesn't go that far. But geometry faked with a texture is subject to mipmapping, giving you good down-sampling to small sizes.

In BrickSmith I am experimenting with replacing primitives with their bounding box based on the size of the part in screen space in real-time - so it's a dynamic LOD scheme, not a net reduction. But in the case with a large number of parts, it's a win: zoomed in, parts are culled off-screen, and zoomed out, many small parts are reduced to bounding boxes, while the big parts are preserved. But the results are medium-quality at's done for performance reasons.

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Decreasing poly count on models - by Nicola - 2013-02-14, 16:17
Re: Decreasing poly count on models - by Ben Supnik - 2013-04-11, 20:51

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