# constraints in assemblies

how do i mate a point to a plane. for example if i wanted to stand a pencil up on its point. physically impossible i realize but hey, its inventor and anything goes.

thanks alot

My suggestion would be to mate the eraser end of the pencil to the surface and then offset it by the length of the pencil to get the tip touching the surface.

Warning I have never used Inventor.

Anyways, I would assume that if you made planes concentric between the assembly and the pencil (right & right, front & front) then it would automatically align itself in the direction you want it.

As far as the point (tip of pencil) to the 3rd plane (top), then you would be able to mate it and everything should be good and you would get your preferred 3rd axis constraint.

I use Solidworks, and this is how I would do it. I don’t know if Inventor would do the same thing terminology wise (ie: mate vs contraint) but the concept should be there.

Have you tried putting a 90 degree constraint between the point and the plane?

I have never used inventor but I think they have a point to point constraint. Creat a plane and put a point on the plane then exit sketch then constrain it

I just tried it, and it won’t let you mate something to a geometric point unless it’s a work point. Try creating a work point (choose the axis of the pencil and the conic surface of the pencil to create a work point at their intersection), then mate that point to the surface. That way you’ll still be able to move the pencil around on the surface.

To constrain it standing up, create an angle constraint between the pencil axis and another edge or axis.

thanks

one time i got something similar to work when i used someone elses drawing and they had used loft to create the point. i dont remember quite how it worked but i think i mated the plane and the work plane need to make a loft.

thanks alot

another strategy would be to cut the end of the cone of your pencil off and create a VERY VERY small plane to work with. In fact This is probably more realistic. Another strategy would be to round the tip off and use a tangent constraint.