Hello,

I am trying to create a complexe ridge with sweep, but it does not work out as planned. See pictures below:

The curve and rail for sweeping :




The ridge created with sweeping. Looks good from one side, but...




not from the other side. It´s not touching where it should.



In yellow you can see how I want it to look like.



I also tried to achieve this by useing two rails, didn´t work. How to do that? Which tool can I use for this? I attached the 3dm file, if you want to have a closer look and try. This really drives me nuts.

Thanks in advance for your help.

Philip

Hi Philip - you can select multiple profile curves when doing a sweep, so if you want it to end in a different shape than the start curve, select both of those 2 profile curves, both the start one you originally used an also the end one that is in the end shape you want before running the Sweep command. That will produce a sweep that also transitions between those 2 profiles as it travels along the path.

However in your case here the end shape you want sticks out a fair distance away from the path and that will cause a bunching / self intersecting type problem since the distance away from the path is greater than the tight bend radius.

That kind of "large distance going around a tight bend" produces bunching and poor surface formation like this:




So probably your given geometry will not really work very well for a sweep, your profile is too long and the sweep rail bends too tightly. It's not exactly clear to me what kind of shape you're looking for in the bending zone there, do you have any images of the type of result you are trying to build?

- Michael

Hi Philip, are you looking for something like the attached result (see attached 3DM file) ?

I constructed that by extruding 2 flat shapes and stopping the extrusions a little distance before they hit each other and then put in a Blend surface to connect them.

The extruded pieces looked like this before the blend was put in:



Something along those lines may be better than trying to use sweep in this case since sweep will have difficulty negotiating the corner bend with the fairly elongated shape sticking out quite a ways, that bunching problem I showed above.

And also if you give Sweep multiple profile curves the sweep shape will be gradually changing between those shapes as it travels along the path but in this case you probably don't want that kind of gradual change and instead want the straight portions to each have a fixed shape along the entire straight portion of the path - building individual extrudes for those straight pieces will get you that.

- Michael

Michael, you are a genius! Thank you very much. The way you made this the corner is exactly the way I wanted it to look like.

I tried for one whole day to do it with sweep, loft over several profiles and so on. It totally drove me nuts. I understood what you did, but I haven´t worked with blend so far. Now I am trying to reproduce your result. Is there an instruction video or tutorial for the blend function? Next time I will post much faster before I put so much effort into it. Your program has a lot of powerful features, I haven´t fully discovered, yet.

Thank you.

All the best,
Philip

Hi Philip, I'm glad that's what you were shooting for.

> Is there an instruction video or tutorial for the blend function?

I think that several of Mike Maynard's tutorials use Blend:
http://www.k4icy.com/tutorials.html


> Now I am trying to reproduce your result.

Because you have a different number of sharp corners between the pieces, you'll probably want to do the blend in a couple of different steps rather than trying to do the whole closed loop in one go (which you can do in other circumstances just not in this particular case).

So to start with to get the main piece, you just select these 2 edges and run Construct > Blend:



That builds an outside corner piece like this:



Then on the inside part, I think I did another separate blend there, then used Network do do the floor part. After you have constructed the various pieces use Edit > Join to glue them together.

- Michael

Hi Michael,

Thank you for your detailed description. That gave me a precise hint how to do it. I worked through all tutorials I could find on blend on youtube. But just now I realized, that the reason I could not do it was, that the extruded objects were solids... If I extruded them without caps, it worked like a charm... And blend does only work on edges, NOT on curves! Did not know that.

I changed the extrusion path of one curve and got it closed! Yes!!!

Before it was not closed. Only a joined surface. Is there some kind of auto repair or detection to find out where exactly your model is not closed?

I really had to get used to modeling with surfaces. Normally I model with solids only.

Alle the Best,
Philip

<< And blend does only work on edges, NOT on curves!

This is not right! ;) (but maybe I don't understand the translation)

A little trick : click on the extremities near between the curves!

<<This is not right! ;) (but maybe I don't understand the translation)

Hey Pilou,

blend does work on curves. You are right, but it does sth. completely different than on an edge. That´s what I meant.

Philip

No problem! :)