Major bug: project curve onto mesh is off compared to nurbs

there is blue curve in the file, try projecting onto nurbs polysurface and identical mesh surface. in top view you will see its off on mesh whereas its correct on nurbs.

i consider this a fatal flaw because i relied on the program and now i have to redo everything. 2hours lost…major_bug_project_mesh_vs_nurbs.3dm (397.7 KB)


I’m guessing that this is because your objects are 1.4 billion mm from the world center.


Yup. Move the mesh to World Zero and a projection done there is correctly aligned.

ok but with nurbs it works even ffo, with mesh it does not. if its possible with nurbs, mesh should perform well as well

You’re working on objects so far away from the origin that whatever results or errors you get are essentially random noise, you’re bumping in to the limits of math on a digital computer. There is no logic that X appears to work so Y should, you’ve traveled to the Quantum Realm where such such concepts break down.

i think we need triple precision numbers for architecture :smiley: coordinate systems usually spans continents and you work with micrometer precision. Or avoid the problem in the first place by introducing project origin but this is long awaited thing not happening yet…

Which is absurd nonsense. You’re saying architecture works with the accuracy of molds for Lego bricks? Yeah okay. You don’t actually “need” project coordinates, if it was that important it would have been added ages ago.

Double-precision floating point coordinates are perfectly capable of representing every molecule in the solar system, but doing math on those numbers is wildly less accurate–and varies across the number spectrum in weird ways. Basically set up your coordinate system to have at max 8 significant digits.

i am not the one to choose my coordinate system we use JTSK coordinate system with origin in baltic sea and we are 1000km from there. If you work in millimeter which is common in architecture and you are modelling steel structures with washers micrometer precision is not too farfetched. Only way to avoid far from origin problems would be to set that this point close to my object is project origin which has relation to world origin just by differential vector. all the math would be calculated from the project origin and world coordinates would just be matrix adding that vector to the coordinates. this is how revit does it for example.