3 ms·

Most Engineering software uses surface models or meshes today. Are there specific advantages of using SDFs here instead?

bhouston 6y ago
I believe it is because sdf are very easy to do constructive solid geometry on. Intersect, union, subtract operations are basically free and robust. Where as with solid geometry robust csg booleans are highly problematic with rounding errors and edge cases galore.
- userbinator 6y ago
  The simplicity is also why the demoscene has made extensive use of them (see the https://iquilezles.org/ https://iquilezles.org/ site for some great examples) --- very complex scenes can be described in a tiny amount of space.
sjkelly 6y ago
Generative design is almost always in SDF form. Things like point clouds, images, and 3DNN also dovetail nicely. SIMP in topology optimization is a good example also. I believe alot of SDF applications are still held back by mesh extraction. There is no silver bullet that can handle adaptive methods, sharp features, and generate a manifold. SDF and mesh extraction are one of my favorite areas of research. I think it is very important for additive manufacturing in particular. The value will be hybrid SDF and spline methods for complex and highly integrated applications such as fluid and heat transfer or compliant mechanisms. Modeling a box or cylinder with SDF isn't the right application IMO. Optimized topology for a given PDE is.
- tdotuos 6y ago
  > Modeling a box or cylinder with SDF isn't the right application IMO. Optimized topology for a given PDE is. Like anything in engineering and design, IMO, it depends on who you are what you are doing. > SDF and mesh extraction are one of my favorite areas of research. Why convert a SDF to a mesh to do visualization and engineering analysis? Even with FDM, which can be thought of a 2D filling problem like scan conversion once you have a SDF, meshless may be the way forward with additive manufacturing as well. One can think of reasons you would have to do mesh extraction, but for niche areas of manufacturing.
mdtusz 6y ago
Especially with additive manufacturing, SDF's are far superior but still not widely used (but I predict this will change very soon). As others have said, many operations are much easier when working with SDF's, but specifically for AM, there are many operations like lightweighting that are extremely difficult to do "correctly" when using normal meshes. For simulations as well, an SDF makes things like voxelization, random walks, and basically everything else that is related to the topology of a part much easier. Check out the company/product nTopology. It's IMO the future for engineering modelling and CAD for AM. I used to work for an AM company and was essentially the internal evangelist that complained about STL's and "traditional" CAD formats that are proprietary or just outright a PITA to work with (I'm looking at you, STEP...)
nness 6y ago
Super niche, but SDF shaders are the approach used with the voxel art tool, MagicaVoxel, to help artists quickly generate geometry/shapes for their artwork.

bhouston 6y ago

I believe it is because sdf are very easy to do constructive solid geometry on. Intersect, union, subtract operations are basically free and robust. Where as with solid geometry robust csg booleans are highly problematic with rounding errors and edge cases galore.

userbinator 6y ago
The simplicity is also why the demoscene has made extensive use of them (see the https://iquilezles.org/ https://iquilezles.org/ site for some great examples) --- very complex scenes can be described in a tiny amount of space.

sjkelly 6y ago

Generative design is almost always in SDF form. Things like point clouds, images, and 3DNN also dovetail nicely. SIMP in topology optimization is a good example also. I believe alot of SDF applications are still held back by mesh extraction. There is no silver bullet that can handle adaptive methods, sharp features, and generate a manifold. SDF and mesh extraction are one of my favorite areas of research. I think it is very important for additive manufacturing in particular. The value will be hybrid SDF and spline methods for complex and highly integrated applications such as fluid and heat transfer or compliant mechanisms. Modeling a box or cylinder with SDF isn't the right application IMO. Optimized topology for a given PDE is.

tdotuos 6y ago
> Modeling a box or cylinder with SDF isn't the right application IMO. Optimized topology for a given PDE is. Like anything in engineering and design, IMO, it depends on who you are what you are doing. > SDF and mesh extraction are one of my favorite areas of research. Why convert a SDF to a mesh to do visualization and engineering analysis? Even with FDM, which can be thought of a 2D filling problem like scan conversion once you have a SDF, meshless may be the way forward with additive manufacturing as well. One can think of reasons you would have to do mesh extraction, but for niche areas of manufacturing.

mdtusz 6y ago

Especially with additive manufacturing, SDF's are far superior but still not widely used (but I predict this will change very soon). As others have said, many operations are much easier when working with SDF's, but specifically for AM, there are many operations like lightweighting that are extremely difficult to do "correctly" when using normal meshes. For simulations as well, an SDF makes things like voxelization, random walks, and basically everything else that is related to the topology of a part much easier. Check out the company/product nTopology. It's IMO the future for engineering modelling and CAD for AM. I used to work for an AM company and was essentially the internal evangelist that complained about STL's and "traditional" CAD formats that are proprietary or just outright a PITA to work with (I'm looking at you, STEP...)

nness 6y ago

Super niche, but SDF shaders are the approach used with the voxel art tool, MagicaVoxel, to help artists quickly generate geometry/shapes for their artwork.