Blend Surface

Hey Guys

Is there a way to get a much more smooth surface blend between the center pad and the insole surface?

I’ve been messing around with the numbers but have no idea what combination might achieve this. I have included my file for your reference. I want to eliminate any indication of sharp lines and want a very smooth transition between the met pad and the insole surface. Always appreciate the help!

Blend Surface.3dm (407.9 KB)

first of all i would duplicate the boarder of the inner part, then explode and delete the outer 2 surfaces from it and untrim the middle one. you seem to have ended up with 3 surfaces where you could have only one.

after that merge the inside edges of the outer surface, you have split that into several parts at some point. keep it as simple as possible. then you could already use loft with matching options turned on, or blend surface with options tangency or curvature of course. for an even smoother transition you might want to trim a bit more from either surface away that the transition can develop more natural, it is after all a bit tight.

something like this:


Thanks Diego and Encephalon!

Diego - I tried following your video but I get lost from 0:21 to about 0:44. Basically when you start making the pipe up until you do some joining and splitting. I am unclear why you need to make a pipe, why you need to split the pipe and run the Blendsrf command that reconnects the pipe.

In addition I would like to learn why the initial steps of exploding and untrimming are necessary.

Encephalon - I did not intend that surface to be in 3 pieces. I forgot I had done that by accident from something I was working on earlier but usually its 1 surface created by a NetworkSrf command.

Thanks for the detailed video!

This is what I am getting for my Blendsrf at the pipe stage

ic. well that happens. i mentioned duplicate boarder above, not sure why i did that, i probably meant in case you have to retrim it again.

besides trimming it like diego mentioned with his video, you can also try offset curve on surface. but important probably also when you blend that surface to juse the option “add shapes” and align the iso direction. best to have perpendicular in snaps enabled as one shot.

create a new surface, then use fillet edge
Blend Surface.3dm (531.7 KB)

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Thanks vikthor. I am hoping to achieve the appearance that Diego achieves in his video above.

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OK. use this and use the tool RemoveKnot

Blend Surface.3dm (503.1 KB)

Hmm…still kind of lost. Would like to get some clarification on the overall design logic. I would not have thought of including a pipe stage and thought I could somehow just find a good blend transition using the Blendsrf command. Seems like I might have some catching up to do!

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It is for the surface you created, @encephalon has been explaining it, you can use the method that I mentioned initially and you would avoid using the pipe command followed by the blensrf command. It would only be Trim and FilletEdge.

try this
Blend Surface-Yo.3dm (811.3 KB)

Hi, I splitted the pipe because it overlaps itself at the middle of the rail. that was to get a clean cutting line at both sides. Basicaly to avoid this:

to avoid the issue you have using the blendSrf on the pipe, you have to pay attention to the seam linea while selecting the edges for the blen, in your case, one of the ends of the seam was wrong :

Got it!! Thanks a bunch @encephalon, @DiegoKrause, and @vikthor!

This one looks quite nice too. What would I be trimming?

in this case you do not need to use a pipe… simply draw 2 curves that define the gap you will blend over. Bigger gap= smoother blend, smaller gap= tighter blend

When we teach level 2 we talk alot about “modeling the gap” with the idea that you are creating the gap for a transition and as such you model the hole, not the surface. does that make any sense?

draw one curve to define the inside of your gap, then copy past and scale up to create the outside of your gap… you can offset, but make sure to rebuild the offset to make a cleaner curve. Offset make a jillion extra points unless you offset using the loose setting-

orrr, you can use the Dave Schultz offset trick- Video : Offset Curve Dave Hack


Hey Kyle,

Thanks for this tip. This way seems more intuitive, not that the pipe method didn’t yield a desired result.

I actually didn’t have issues offsetting my curves. Immediately the resulting curve had the same amount of control points as the first one so I did not need to rebuild. Perhaps I have some presets in place that I am not aware of. All in all, this is a great tip and will give me another option to achieve this result.

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Offset with Simple=yes, keeps the same number of control points, but the results are not within modeling tolerance.

Offset with Simple=no, makes curves within tolerance, but has to add control points to make the tolerance fitting possible.


Thanks for the clarification @John_Brock. I can recall many times when I needed lower control points and thought I would have to just live with sacrificing the tolerance of the curve.

Dave’s offset hack makes for a closer approximation of shape than offset loose in my experience.

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I create a lot of fillet blends using Pipe to trim. My go to trick for the Blends is to do them Positional. Then Surface match preserve isocurve direction to prevent wiggly isocurves.

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