MatchSrf bugs

MatchSrf command ignores some edges that I have selected, ignores some options, and sometimes uses the options I used last time, rather then current options.

Hi Andrew, MatchSrf does all of these things even without bugs, so an example would be helpful.



Please send in a 3dm file with a detailed description of all the steps that are necessary to replicate any buggy behavior. ‘Sometimes things don’t work’ is not likely to help fixing anything.

I have selected the last option (Make perpendicular to target edge), but it isn’t.

junk.3dm (97.5 KB)

Hi Andrew - it looks that way here

What did you expect to see?


Sharp, 90-degree kink at one edge.

When I select left edge first, the new surface is not twisted. When I select right edge first, the new surface is twisted (as shown below.)

From Help:

Select an untrimmed surface edge.

Select a surface edge or curve to match.

Pick the two surfaces near same ends. This surface can be either trimmed or untrimmed.

It’s the end of the edge that you pick that counts.


It does work. Thanks.

I have rotated both surfaces and saved them as new drawing: junk2.3dm (99.6 KB)

Then I ran the MatchSrf command again. I picked up top edges, but the command picked bottom left edge instead (as shown below). Changing the options does not solve this problem.

Looks like top edge to top edge to me…


Top edge on the right side, but bottom edge on the left side.

I duplicated edges of both surfaces (from junk2.3dm) and used Match command. I picked both curves near top ends, and the same problem was replicated with curves. I reversed direction of the left curve, but it did not help.

Both results look correct to me- perhaps you are expecting something from Match that it just does not do. What result are you looking for?


New curve which joins the tops of old curves (shown below).

Use BlendCrv for this. Help describes what the commands do.


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Thanks! BlendCrv and BlendSrf work well, but it seems that Match and MatchSrf should work too.

There are more problems with the MatchSrf command:

  1. Some options in the MatchSrf window do not update the display. You have no idea what you will get until you complete the command.
  2. When the MatchSrf window appears, there is no way to change any option in the command prompt.

Regarding your first comment about updating the display after changing options, sometimes the options don’t change the output enough to be noticeable.

Another problem: “preserve other end” option does not work. No matter what option I choose, I get no constraint.