Solid loft failing between two simple profiles

[markD2LV3]

I have two innocuous profiles as shown in the three attached images and cannot get a solid loft created between them.

I get an error message as shown in another attached image.

Am I missing something? Please help. Thanks!

[jhackney1972 · Accepted solution]

Try adding rails between the vertexes of each profile.  Also attach your model for others to take a look at.

[markD2LV3]

Yes, it works with rails. Normally simple lofts like that also work without rails - so that's what seems odd to me.

Well, my file has a lot of other stuff in it and that's why I did not initially attach the model. Now, I copied and pasted new the sketches into a model I intended to attach to this message, and all of a sudden the loft worked. Buggy behavior, I guess.

Another question I have is how to tell the loft which points on the profiles to connect. I guess only through rails. Shark FX I used before allowed you to specify point to point connections without rails. It's not a biggie but would be nice to have.

[jhackney1972 · Accepted solution]

You make another sketch, it really does not matter which plane, just choose one that is not on the same plane as the profiles normally.  Then make sure 3D Sketch is checked in your Sketch Palette and sketch between the profile points you want to map in the order your desire.  See screencast.

[markD2LV3]

Yes, your screencast was very helpful. Thank you very much for taking the time to make it.

[jeff_strater]

If you can extract just these two sketches into another design, I'd like to take a look at it.  There should be a way, using Loft "point mapping" UI to get this to work without rails.  Thanks!

[davebYYPCU]

Point mapping will work if you can get the preview, and then manipulate,

but without the preview you are ......

[markD2LV3]

Jeff,

I actually have three sketches. Initially even two would not work. Now, when "pasted new" into a new file they work. But I still don't know how to do "point mapping" in Fusion.

The file is attached. Thanks for taking this up.

[davebYYPCU]

Loft is finicky, I get the error if selecting right to left, but not left to right.

Point Mapping, is in preview stage, those big white dots can be moved for effect, tedious but needed sometimes, each can be click dragged along the profile edge, but must not cross over / past its neighbour.

No Rails....

Might help....

[markD2LV3]

At least there is a way to map the points. That's important.

And I do think lofts need to be really robust - they are so useful.

In another instance, I'm also unable to use for rails or profiles curves that consist of two splines that are "joined". The problem is I don't know how to join two splines (or any other curves) into one at the point they touch each other. And the loft command selects them separately even when chain selection is checked. Oooph...  Makes me want to really master sculpting : )

Thank you for your help and the pictures - very helpful.

[davebYYPCU]

Rails, a whole other ball game, 

Quick answer is the small blue snapping square will appear if you are drawing your connected spines, but 

Projected Splines, I found out recently they are a best approximation.  You have to break the link on one side and make the end points coincident.  Lost a few hours on this in the past, 

The long answer is to use edge loops of helper bodies, works a treat.  Design dependent, I know.

(Trippy finally got the penny to drop for me)

Might help....

[jeff_strater]

@davebYYPCU answered most of the questions here - yeah, for point mapping to work, you have to get a preview.  If you get a preview, though, you can manipulate them.  I see the same problem - Loft in one direction works, but not in the other.  That's a bug that I'll log.

Here is a screencast of point mapping in action.  The one hidden easter egg here is that if you double click on one of the point mapping points, it will select all of them in that profile, and that can be useful if the default mapping is off by one.

But, if you really want control, use rail curves.

[markD2LV3]

Great, the screencast has made the point mapping clear to me. Thanks.