Finding the U-V parameters of a surface

[Mr. Abhishek Sanghani 0]

Hi All

 

I'm new here. Could I get some help on obtaining the normal at a specific point of the surface, if I only know the x,y,z coordinates of that point? It seems easy to determine the normal if i know the UV of the point, but I'm unable to find a function that can return the UV value just based on the x.y,z coordinates.

[Mr. Claus Abt 14]

Hi Abhishek,

One option:  create a projection point, e.g. at given x and y, project a point onto the surface. This projection point can give you the information about its U and V position on the surface. I have attached a small project that implements the normal as a line.

If you need such a normal more often, it might be useful to encapsulate such a setup in a feature.

 

Cheers

Claus

 

normal.fdb

[Mr. Abhishek Sanghani 0]

Hi Claus

Thanks for your help.

 

I figured out a similar way to sort out the problem. In my case the point lied on the surface, so I used it as a source and took [0,0,0] as the direction. That gave me a a point at the same location as the source.

 

I would really appreciate it, if you could let me know- when using the normal to a surface at a point, which direction is used conventionally? Could the normal be flipped for a surface (to point inwards or outwards).

 

Best Regards

[Mr. Claus Abt 14]

I am expecting that our software returns the mathematical defined normal computed from dU/dt x dV/dt (right hand, thump U direction, index V direction and middle the positive normal direction). If you want to switch to the inside you can substract the normal.

 

e.g.: line normal(onSurface, onSurface - surface.getNormal(onSurface,getU(),onSurface.getV()))

 

Cheers

Claus