Problem lofting periodic curves and a circle

I just started with Grasshopper and with some help I build the model attached. (So the periodic curves are OK since somebody else did this for me)

I have 4 almost similar periodic curves (sine functions over a circle) which loft perfectly (still have to adjust the loft at loft options)

As fifth element/curve, I created a circle. When I want to loft the circle together with the 4 periodic curves (circle has only {0} in the panel, the periodic curves have {0,0,0} I think the problem lies here, but I don't know what it means) the loft option goes red:"insufficient valid profile curves"

I created several ways to build a circle....(3 options, see the model attached) but it won't work.

Can anybody help me out to make to loft working? Thanks in advance!

In the end I hope the loft option will work so the output can go into the Divide and Subsrf button, to create a grid.

And I still need to set the loft options to tight and refit, to make the loft smooth.

Attachments:

Model2-grasshopper forum.gh, 43 KB

Replies to This Discussion

Permalink Reply by Carl Christofferson on March 13, 2014 at 9:03pm

You are right that the problem lies in the data tree branching. Just right click the loft input C and select flatten and that should do it.

Basically the {0} is the branch path name, and because the curves are in paths with different path names, they will be treated separately by the loft component and not added together. Flatten removes all branch info and puts everything into the same path.

You can search the forum about data tree structures for more info, when you want to learn more about it :)

Permalink Reply by Mirjam on March 14, 2014 at 1:13am

Dear Carl, thank you very much!

However, when I flatten the loft, I get 2 lofts....1 loft with a neat surface between the 4 periodic curves and 1 loft due to the flatten command: he goes immediately from the lower periodic curve to the top curve (which is the circle). So like you can see in the picture, it won't give the result (a smooth loft through 5 curves) we want.

Any suggestions?

Attachments:

Model2-grasshopper forum.gh, 44 KB
2 lofts.JPG, 30 KB

Permalink Reply by Carl Christofferson on March 14, 2014 at 2:39am

Ah yes, I forgot to mention that the input order of the curves also needs to be in the correct order you want them to loft. Because the circle had a path of less branches than the sinus curves, it was put first in the list even tough it was input as last in the merge component, this order then remained even after the flattening.

A solution can be to either flatten the inputs of the merge component (instead of the output) to be sure the order isn't shuffled, or use two merge components to change the order (less clicking).

Attachments:

Model2grasshopperforum (1).gh, 47 KB

Permalink Reply by Mirjam on March 14, 2014 at 5:45am

Thanks Carl! I opened your file in my grasshopper (I still have to update it to the latest version so that might be the problem) but I didn't see the sinus curves (only a loft between 5 circular curves). BUT instead you helped me a lot by saying that the circle would be put first in the loft procedure, so the only thing I did was reversing the order (working from top to bottom, with the circle first and then the 4 sinus curves)

And now it works perfectly!! (for now haha) :)

Attachments:

Loft.JPG, 22 KB

Permalink Reply by Mirjam on March 14, 2014 at 5:54am

The only thing now is that the outcome of the loft is an open Brep, and when I put this outcome in the I-Divide and S-SubSrf it turns red (error: data conversion failed from Brep tot Surface)

Considering this discussion http://www.grasshopper3d.com/forum/topics/how-to-convert-the-open-b...

It seems nothing is possible to make an open Brep into a surface (?), or something that will work with the Divide and SubSrf to create a surface.....(untrimmed surface) Is this correct?

the model is still the same, but I will attach it.

Attachments: