Sweep - Blend Options?




I am running a simple sweep along a curve. I am doing this in sections so I have more control, since the curve is complex.

Is there an alternative to global shape blending? It seems my choices are linear, which kills continuity with the next sweep section or GBS which is a strange function. I would like control over the transition and also to maintain continuity with the next section. I’m use to nice falloff controls in Modo.



Without a file, what can one say?

(Miled Rizk) #3

without the file it’s difficult to say. but i will just guess what might the problem is.
let’s say you have two surfaces that are not yet connected, you can use blendSrf command to blend two surfaces
by choosing the surfaces edges. a dialog will open and you can choose the type of continuity you like.


Thank you for your responses. See image. I assume blend surface is not what i am looking for because it will not follow a spline like sweep.

I want to have a nonlinear, continuous transition, but i want control over the transition curve. Seems very reasonable. I’m sure there are workarounds that might work just fine with a straight spline like this example, but not with a long complex spline.


how much control do you need? for round profiles you can use the command pipe, which lets you choose as many radii you need. this pipe can also be edited with surface points turned on.

if you have square profile curves or anything else then you simply add more profiles. if you need something like continuity control over the transition you can make a preliminary sweep extract a few open curves for networks surface and use those including the edge of the adjacent surface you want to transition to to make any kind of continuity you like.

if you have a straight curve as shown here a loft would give you all the control you need, so a more defined/real situation of what you are dealing with may help to find a fitting solution.

(Pascal Golay) #6

Hello - can you post the curves that you actually want to sweep? I understand what you’re suggesting, I think, and seems like a reasonable thing to think about, but it may be possible to help in the meantime if you post a file.



Seems something for sweep2
Orient with 3d scaling in the parts you want more control should do.
Blendsrf can also give more control if you use curvature or higher


test.3dm (423.5 KB)

Here is an example. I dont want to use 2 rail because then i have to worry about the distance and orientation of both rails. Blendsrf is not a solution because it will not follow a rail. It seems that Alias has manipulator controls for sweep - https://knowledge.autodesk.com/support/alias-products/learn-explore/caas/CloudHelp/cloudhelp/2014/ENU/Alias/files/GUID-CBC26CEF-6EA0-4F5A-898C-2C620B1319E8-htm.html

It seems limiting to only have two arbitrary choices for how the profile changes across a rail.


(Pascal Golay) #9

Hello - just curious, why not sweep all of these profiles in one go? Or did you do that and split it up?



Hi Pascal,

Because then i have no control over how the width or rotation goes along the rail. I would like these controls as well - rotation and width, but my workaround was this segment approach.

(Pascal Golay) #11

Hello - I understand placing multiple profiles, but I don’t see, yet, why you’re not including them all in a single sweep. With History enabled, you can then rotate or scale the profiles to adjust. Maybe I’m missing what you’re asking…



to be honest, i am now forgetting why i did not do this. I feel like there was a reason, but now im not sure and blushing a bit.

that should fix everything and I’ll only get a subtle version of this issue over the length of the whole sweep now?



Hi Pascal,

I ran the sweep as one continuous sweep and it did not reduce the amount of ballooning/distortion cause by the transitional issue. In between each profile is that strange ballooning transition.