I create a simple rectangle. Then I round one end by making a circle that is tangent with one end and the two sides and trim the two corners and the inside half of the circle off. I then join the half circle and the three sides of the rectangle into one shape. I then extrude this shape into a solid, but no matter what I do I can't get it to cap the ends. Even if I select "cap ends" it won't do it. I back up and just select the shape and try to create a plane. It won't do it. I can't figure out what is wrong with it. Can you help?

If you go to front view and look at the left area where the top curve meets the verticle line, you will see the problem. If you select it and view the properties label, you will see it is a curve, not a closed curve. You can run edit-trim and select that item, then zoom to that left corner I mentioned and select the little piece to delete and it will be a closerd curve and extrude solid.

Here's a picture of it.

Hi Mark, thanks for posting the model as well, that really helps to see what is happening.

Burr definitely has the right answer there - during the trim the intersection points were just a teeny tiny bit off so the circle piece you got was not actually a 180 degree piece, it is just slightly over that, so that's where the outline is not closed.

Just in case you have any problems following what Burr said, I have attached an updated file here which should now cap for you.


I can repeat the problem with Trim over here, so I'll take a look at what I can do to make that work better.

- Michael

Thanks, guys. That kept me going.

Hi Mark, for the past several days I've been looking into this problem you had with just a rectangle and a tangent circle trimming each other, and I've got several fixes in this area for the next beta release.

To start with, there was a bug in Join introduced in v2 where it would not close off the very first and last segment in the loop in certain conditions (when other pieces joined at a tight tolerance and the first/last segment were at a looser tolerance level but still within the maximum join distance).

I think that was the main problem here, and that one is fixed up for the next beta.


I also added some other stuff in this area as well - lines, circles, and arcs will now be handled using a special analytic curve class which is able to handle intersections between lines and circles with a special case handler that has greater accuracy.


I also added a different special case handler to the Circle/Arc Tangent command for the case of putting in a tangent circle inside of a rectangle, to calculate that case directly (with higher accuracy) rather than going through the iterative solver mechanism.


So I think these things will help to avoid this problem you ran into here, at least as long as there aren't any new bugs introduced with them that is.

- Michael