What formula can I use to calculate the info given by UVHelper?

[Neil_Burkholder]

I’m trying to calculate the same information as what is given by the SketchUp::UVHelper class, in C# where I don’t have access to this neat class.

I would like to be able to input the normal vector of a given mesh (face) and then input any point3D and be able to receive output as a point2D. I’ve searched for several days and simply can’t come up with a formula that works.

Does anyone know what formula the UVHelper uses to calculate the UV positions? @thomthom? @DanRathbun?

Here are some more questions I have posted.

UV Mapping & Texture coordinates - HELP!

This questions is not necessarily SketchUp related, but I’ve been trying to figure out texture mapping for several days and am not making any progress. So in SketchUp textures can be assigned to any face an the texture points ‘up’ and is automatically sized and positioned correctly no mater what the plane is. Consider the following picture where my texture lines run vertically. When the top is flat the texture runs along the green axis. [image] However when I give some slope to the roof fa…

How to set Texture Coordinates properly for Mesh3D

[Neil_Burkholder]

Finally found my answer here.

How to convert a 3D point on a plane to UV coordinates?

[tt_su]

Several years ago Andreas wrote a post on SketchUcation about how the UVQ values worked: [Tutorial] uvq coordinates, or: The Magic Q • sketchUcation • 1