Blend differences

Rhino Rhino for Windows
1

When I do curve blends on the two right corners I get different blends. I have tried to make sure the upper and lower horizontal curves are identical and the right vertical curve is symmetrical.
However you can see the difference on the blends and the Length command confirms it. What am I doing wrong?
Nick
blends.3dm (33.2 KB)

2

Hi Nick- the vertical curve is not symmetrical on that horizontal axis…

-Pascal

3

OK I got that. Thanks. But, after I carefully trimmed the curves in half, then mirrored the halves and matched, then aligned the corners, then mirrored the right and bottom to the left and top, I still got different blends.
Then I realized that the blend starts at the point where you pick the curve. Nothing on the command line or the Help file indicates this. It’s a bit crazy making for the uninitiated.

4

If the curves meet at the ends, then the blend starts at the pick point- personally, I would prefer that were always the case but I can understand how that might be bad if you picked very near the end. Maybe a FromFirstPoint option would do it. In any case, you can slide the base point along the input curves.
-Pascal

5

It would be useful to have the info in the Help file. @margaret

Thanks for your help here.

6

I added a note to the help. It should appear in the Web Help version in a few days. If more information is needed, let me know.

http://docs.mcneel.com/rhino/5/help/en-us/index.htm#commands/blend.htm

7

thanks!