Spatial index data structures can be used to quickly cull large sets of triangles by determining if parent bounds are entirely encapsulated by the lasso shape or do not intersect at all which can give a bit of a performance boost if needed. Otherwise the triangle has not been intersected.If they do then the triangle intersects the lasso shape. Check if any of the triangle line segments intersect any of the lasso line segments.If any of the crossing numbers are different between the points or if any of the crossing counts are odd then the triangle intersects the lasso shape. Check if any of the triangle vertices are within the lasso shape, which you can use the ray-crossing algorithm for.Project the triangle vertices and edge segments into screen space. Ratings and Reviews Prior to this update, it would take me 5x longer to make a decent looking model in this app using whatever sculpting workarounds I could.To determine whether a triangle intersects the lasso: If it is then consider the triangle selected. Luckily for us, there is another modeling technique especially suited for modeling organic shapes and it’s called sculpting.

For every triangle in the geometry check if any part is within the lasso.Construct a list of screen space line segments that represent the lasso shape drawn by the user.Here’s a rough overview of the algorithm I used for finding the lasso selection for every triangle that intersects the lasso shape: Depending on your use case performance may be good enough without an acceleration structure.

Sculptgl models