Here is my shape - has inside and outside profiles because the loft needs to be hollow. I would like the bottom to be flat.



And here is the result. None of the lofting options seem to help. What am I doing wrong?



Thanks, Andy

Hi Andy, can you please post the .3dm model file that corresponds to your screenshot?

The Loft command expects to have a set of cross-sections, not any rails. You're getting a chaotic result because it's trying to use the rails as cross sections.

If you want to do a loft with guide rails use the Sweep or Network command for that not Loft.

But if you can post your model file it would make it easier to give you a recommendation.

- Michael

Also from what it looks like maybe the Blend command would be good for that:





- Michael

Here is sweep



For blend I have to split my end profiles up and do multiple blends?

Andy

You can Blend any "alone curve" to another "alone curve"

you can Blend any "edge from a surface" to any other "edge of a surface"

Here is blend:



Andy

Hi Andy, can you please post the .3dm model file for your object instead of only screenshots?

For sweep you need to separate pieces out so that you are doing them with 2 rails a time.

For blend you need to hide any curves so that you can select edges and also the edge should belong to only one face so you should delete faces to make an opening before doing the blend.

I can demonstrate either of these on your file if you will attach it. If you need to keep it private you can e-mail it to me at moi@moi3d.com

- Michael

Nearly there with using sweeps - it's fiddly having to construct eight sweeps rather than just doing two "lofts" like I would do in Alibre Design.

I have two sweeps left, as you can see this one does not follow the guide lines and instead creates a bulge. What am I doing wrong?

Well, I tried uploading an animated gif but I get:

"500 - Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed."

Andy

Hi Andy,

re:
> "500 - Internal server error.
> There is a problem with the resource you are looking for, and it cannot be displayed."

Is it a very large file? It may be over some kind of size limit for uploading.

- Michael

Hi Andy, so to solve your light grey visibility problem, do a Ctrl+Left Click on this swatch and set it to black:



- Michael

Andy - It looks like you're making an air duct adapter to bridge between a 4-sided opening and an 8-sided opening.

As Michael indicated, selecting the edges on the 2 openings and Blend is the easiest solution.

You note that you want a flat bottom. For that reason I would use a Network.

Draw 4 curves to connect your 2 openings. In the Right View, note the 2 bottom curves highlighted in yellow - I drew those flat.

Select the 2 curves that make up the 2 openings, the 4 curves you drew to connect them, and Network.

Ed Ferguson

Hi Andy,

re:
> I have two sweeps left, as you can see this one does not follow the guide lines and
> instead creates a bulge. What am I doing wrong?

It looks like you're not doing anything wrong, but sweep is having some problem with automatically determining the proper orientation of the profiles.

Try using Network for that problematic one instead of Sweep. With network select all 4 boundary curves before running it.

- Michael

I tried network and it just gives me a weird crease each time...sigh...



Andy

Hi Andy, the weird result is a bug in Network that can happen when it splits up a large surface at creased spots.

Try a smaller network like in the attached file:





- Michael

I don't follow - I have to network each side separately? So that is a total of eight networks?

Andy

Hi Andy, yes to avoid the bug you ran into you would need to do the networks separately.

But it looks like you've already done many of them with sweep, the one I posted was using Network in the spot where sweep isn't behaving well.

I have a fix for this creased surface splitting bug which will go into the first v5 beta.

- Michael

The problem I see with putting bug fixes into the next beta is that there is no release schedule. I can understand that for new features but IMO (as a professional software developer) bug fixes should be pushed out more frequently. Why not gather a few up and make a 4.1 release?

That way the V4 users can have the bugs fixed without needing to use beta software or have bug fixes potentially stalled while new features are added?

Andy

Hi Andy, the problem is that every change including bug fixes can have side effects causing other problems.

Haven't you ever experienced this problem with a software update causing something unexpected to break?

I like to have a long beta period and then once that period is over it's good to lock down that version and only update it with critical fixes such as if it won't run on a new operating system release.

- Michael

Regression testing.

Hi Andy, that would work if I had a QA department.

Since I don't, the most effective way to prevent regressions is to not make modifications to a stable release.

My process is that modifications go into beta releases, not stable releases.

- Michael