Can't make patch surface

Hi there. I’m having trouble getting the patch command to work on this surface. Also tried Curve network with no success. Any input would be much appreciated. This project is for an air filter mask for Docters and nurses treating Covid19 patients.


JoelSV2_T15_Assembly - Filter Adaptor - V7.3dm (661.4 KB)

Trying to patch area within the pink lines.

extrude the pink lines normal to each one to have tangency directions, then using patch you can pick surface edges insted of curves.

Nice thanks. Will give that a shot now.

that’s why I made this extrusion on your previous topic:

I think that cleaning a bit your objects you can do the same in this case.

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Surface patch should only be used when all else fails. I can’t open your file so I did my best to approximate it. You can get a good result with blends and trims. Y1 Y2


Hi Joel - given the curves you have, I’d put it together something like this-

SV2_T15_Assembly - Filter Adaptor - V7_PG.3dm (647.8 KB)


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Wow fantastic. Thank you guys so much. Extremely helpful!!

Because of how the piece is oriented, it is better to resort to a blend and you get off the subject quickly
Filter Adaptor.3dm (1.4 MB)


Hey Pascal, wondering how you created this. The dark blue and pink surfaces look like they could be 2rail sweeps? Which tool did you use to create the gray surface I have selected?

Thanks again.

Run Untrim on the grey surface to see its original shape


I see that you are using solidworks, this would be another way to do it from the program you use

2.IGS (4.5 MB)

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Hi Joel - All three surfaces are lofts. Some have been ‘noodled’ at the point level quite a bit, as well as subjected to ChangeDegree and InsertKnot and MatchSrf. As you suggest, Sweeps might also do fine here - I did not try it - I tend to make sweeps second choice, because they often make fairly dense surfaces right off the bat, and I prefer to have more control of that.
I’ll try to make a blow by blow file if I can in a bit - but the main thing I wanted to suggest was the layout of the surfaces - getting four-sided surfaces to work in that awkward shape.


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Ah fantastic. Thank you so much.

@vikthor approach with just widening the trim section.


Nice, Stratosfear, what tool did you use to create that middle section? Is that a blendsrf? Any details on that would be helpful. I’ve been having trouble getting surfaces to match up smoothly, without having a small crease left over from where the surfaces come together. Thanks.

I have to rebuild this part today for an updated fit. You can see how the reflections don’t match up well, where the surfaces meet:

I’d just use surface blend. Tangency for the pipe form, make sure to position the surface seam on the outside. So the trim doesn’t cut across it. Then Curvature for the trim blend. Then surface match Tangency to the flange ends.


Nice, Thank you!!