3D and 2D points not matching

Lee_Hesketh

Hi all, hope you had a good Christmas and Happy New Year! I have encountered a problem yet again with my mortise and tenon script. I used the worldToPlane() function to use as a reference point for skRectangle(). I debugged the 3D point and added vectors to get the correct width between the two points and that works. The problem is that when I convert the 3D coordinates to use on the plane, draw the rectangle and then extrude, it doesn't extrude where I want it to and I don't know why.


Here is the file:https://cad.onshape.com/documents/580b256ade95e210af0261d8/w/1d22e17d9b07548059b7b311/e/119330903d9f0efa384481b9
Thanks
Lee Hesketh

NeilCooke

Hi @Lee_Hesketh - please try worldToPlane3D() to see if you get the result you want.

Lee_Hesketh

@NeilCooke I just tried it and this error pooped up : Precondition of operator+ failed (@size(vector1) == @size(vector2)). I assumed it was because one vector has 3 coordinates and the other two, but doesn't skRectangle() need 2D vectors not 3?

NeilCooke

It does, so I would usually do something like var vec1 = vector(vec2[0], vec2[1]);

Lee_Hesketh

So would that be using the worldToPlane3D()?
Also could you explain what you are suggesting please?

NeilCooke

Sorry I was misleading you there - we changed the code of how those functions worked a while back and thought that might be the cause.

I think it is just an error in the sign of your maths and where the origins of the face are (if you still can't work it out, post back)

Lee_Hesketh

I don't think it's an origin issue. What I'm doing is using evPlane() on intFace1 to use as the plane for worldToPlane() and vertexPoint as the coordinates to convert to 2D. Then I am simply taking those coordinates and translating them by adding another 2D vector. It works in 3D as shown in my image, the red dots. The error seems to be when using worldToPlane(). Could it be that onshape doesn't know which axis intFace1 is facing? i.e. it doesn't have an x direction. Before, I was using the Plane() function and using evFaceTangetntPlanes().x but now I am just using evPlane(). Could you possibly use your featurescript mastery to help?

NeilCooke

Not sure I follow this logic - surely centrePoint1[0] is never going to equal vertexPoint[0] from the graphic above? If I comment out this code it looks good? Where should it be offsetting from? vertexPoint or centrePoint?

      if (tolerantEquals(centrePoint1[0], vertexPoint[0]))
            {
                if (centrePoint1[1] - vertexPoint[1] < 0)
                {
                    h *= -1;
                    width *= -1;
                }
            }
            if (tolerantEquals(centrePoint1[1], vertexPoint[1]))
            {
                if (centrePoint1[0] - vertexPoint[0] < 0)
                {
                    h *= -1;
                    width *= -1;
                }
            }

NeilCooke

BTW I presume you have seen my M&T script? 
https://cad.onshape.com/documents/57ebf15e06acf910d5ac1b09/w/5ad1d8c8be840c2c6f8f02b6/e/242e3449f5f40725d9f585ab

Lee_Hesketh

I have seen your script, but I wanted to add more functionality since I am a woodworker, I use a face side and edge to reference against when marking out. Regarding the code you posted, that is for rails that are perpendicular to the ones posted in the graphic, then they have the same x coordinate. For the ones in the picture, they have the same y coordinate, so it skips the first if statement.