Normal at point is returning Null

I’ve imported an SAT made up of multiple surfaces. Because each surface has different U/V spans, trying to get uniform points on the surface is impossible (at least, I haven’t found a way to do this). So instead I’ve created a bounding box, created uniform points on that and projected those onto the polysurface. Now I’m trying to find the normal at each point. When I use Surface Normal At Point, Surface is connected to polysurface and point is connected to a flattened list of all the points on the surface. The list contains to empty or null nodes, however the surface normal at point is returning null for all normals. For some reason it worked on another series of surfaces that I turned into a polysurface, but not this. Any insight is appreciated, thank you.

@haneifk Could you please provide light/small versions of the files with the relevant elements.
Also a wider screenshot (showing all/related nodes) with expanded error messages would help

Hi Vikram, here’s a screenshot showing the whole process. The warning for normal at point reads:

Warning: Surface.NormalAtPoint operation failed.
Could not determine parameter of non-manifold Surface

Ultimately, I’m trying to get a uniform set of points on an organic surface with a non-linear UV structure (so far I can manage getting uniform points on surface by using the bounding box method i stated earlier), and then use those points to place objects such as circles (or other shapes) and then extrude those normal to surface at each point. I’m a new user so if my approach is wrong I would appreciate any and all advice, thank you.

Also, if I connect GetItemAtIndex (the bounding box face that was used to project points) to the surface in getNormalAtPoint, the error goes away, but all the extrusion are now normal to the bounding box surface, not to the head surface.

I just wanted to let you know I got it work. I just used GetItemAtIndex from Geometry.Import. The index was the the full head surface, and then it finally worked.

1 Like

hi to all
@haneifk you has resolve in your specific case, but in this way you calculated the normal at point only at surface’s specified index .

i have the same problem as you but with surfaces of a doorpanel (main surface with fillet etc.) .

i’ve joined all the surfaces in a single polysurface, but i can’t calculate the normal at points on this polysurface.

i’ve got this error .“Warning: Surface.NormalAtPoint operation failed.
Could not determine parameter of non-manifold Surface”

any solution ?


how can i calculate normal of polysurface ?

perhaps by opening a new thread :slight_smile:

1 Like

…and uploading an rvt, dyn & a screen grab (zoom in until you can read 1 node and click the camera icon on the right of the screen)…