Blend Surface - changing continuity makes uneven surface

Hello all,

Has anyone else noticed this? When I create a blend surface and keep the blend value the same for both edges, The surface gets uneven when I change the continuity. I have to go back into the blend value and set them back to the same values again to get the blend to come out even.

Step 1, blend srf

Step 2, change continuity, but not the blend values. Surface is lopsided.

Step 3, select the blend values and hit [tab] to re-enter the value and the blend evens out again.

Am I missing something here? If not, can this be fixed in a new version? I would expect that the blend should stay even when switching from one type of continuity to another. I’ve missed this a couple of times and had to go back to recreate the blend once I noticed it wasn’t symmetrical.


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Hi Mike - can you post that green surface? Clicking in one the continuity radio buttons (even without changing the contiunuity) should reset the blend on that side.


Blend Surface.3dm (888.8 KB)

Hi Pascal,

Here’s the file. I hadn’t tried clicking on the radio buttons again. I see that sort of works too. I have to click on the opposite button to get it to straighten out.

So if I click on Edge 1 Tangency, then Edge 2 Tangency to get the continuity I want, I have to click Edge 1 Tangency again to even it out. If I click on Edge 2 Tangency again, it doesn’t do anything.

I find sometimes just clicking in the blend value boxes gives it the slap in the head it needs to reset correctly. been this way for as long as I can remember.

Yeah, so, it looks like the state of the other edge influences what the base point positions are. So you have to go back… I’ve never specifically noticed that before.



Pascal, your video posting helps a lot to visualize the solution. Thanks!

Are you reporting it as a bug? I wish to follow.

Hello - I am not yet sure that it is a bug - since the reset settings on one side are different depending on the condition of the other side, this might just be how it is, but I will add it to the pile for the developer to look at - I do see that BlendCrv in an analogous situation does not do this - one click on each side is all it takes.


Thanks for looking into this Pascal and kicking it up to the developers. I expected it to run like BlendCrv and was surprised when I ended up with an asymmetrical blend.

  • Mike
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Yes because here is clear but if the starting surface are 90° to each other or less, then is more difficult to notice.


This whole thing of similar commands not responding similarly is very hard for newbies and pretty annoying for vets, who have had to learn (many times a hard way) each and every special case and then remember them all over sometimes long intervals between uses.

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RH-54658 is fixed in the latest WIP


Thank you! I look forward to trying it in the next WIP! :+1:

Just tried this in the new WIP and it works perfectly. Thank you!

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