Loft would flow in an invalid direction?

[hubblebot]

Hello,

New to Fusion 360 and trying to figure out an issue with lofting!

-So I've imported 5 different svg sketches onto different offset planes, and now I selected them all to loft them together. The problem is I get a "loft would flow in an invalid direction" error. It suggests that I "try adjusting the continuity settings:" and I don't know what those are. As far as I can tell visually there's no issue, unless the shapes are too complicated or something. 

I tried lofting with just 2 faces, but nothing changes. Any help would be greatly appreciated, thank you!

[TrippyLighting]

Yes, the shapes are too complicated as each profile constitutes a very complex curve. If you can share your design maybe we can find other ways to approach this.

[davebYYPCU]

I have recieved that message a fair bit recently, but persevered, and after selecting the first rail, it went away, 

but in your case, no rails shown.  

If your preview fails with two profiles, then Trippy is likely correct, profiles are too complex.

[hubblebot]

Thank you both for responding! After messing with it a bit more I found I could get 4 out of 5 of the shapes lofted, if I started from the second to smallest one.

And strangely I could also get the smallest and second to smallest ones to loft as well.

But not altogether. In any case, you can probably tell the result of 4 didn't give me exactly what I was looking for. Would somebody be able to recommend another way for me to create a 3D head model using fusion?  Thanks!

[hubblebot]

Thank you for the explanation! I was able to get either 4/5 or 2/5 of the shapes to loft, if I started with the second to last shape. 

But as you can see, the shape it created doesn't really resemble the head I was trying to make, so I am looking for a recommendation on how to make the model using another tool in the program. Thank you!

[laughingcreek]

If it's a head your after, There is an excellent free program called "MakeHuman" (go to makehuman.org)  that will output a quod surface mesh of a human in OBJ format.  This OBJ will import into fusion and convert nicely to a tspline.  This is a work flow that I've seen @TrippyLighting talk about many times, so he may be willing to give you some help with specifics. 

[hubblebot]

Thank you, but I am not looking for a model that elaborate or realistic. I would like to make it myself in fusion! 🙂 If it helps, after designing the head in fusion, I plan to import it to TinkerCAD so I can make some more simple modifications. 

[davebYYPCU]

Keep your profiles.  It's only the detail from eyebrow to chin that needs a lot of push and shove

Try Sculpt, manipulate a quad ball to match those profiles.

Having said that, 1st to admit - I have no experience in that area, but see impressive results.

Might help...

[TrippyLighting]

Aha. You don't like doing things the easy way 😉 That's cool with me!

Well ..then here's a tutorial that describes how to model a head in 3DS Max. You can apply very similar principles in the T-Spline environment, where you would definitely start this in box mode.

I looked particularly for a low poly tutorial because most beginners either use way too many polygons or ay too too little.

The trick is to start with a low poly count and then add detail where necessary. 

Modeling in box mode will ensure that your model will look good when in smooth mode. It it resembles what you want to model in box mode, it'll be fine in smooth view mode.

[jeff_strater]

Hi @hubblebot,

The "invalid flow direction", I would have to look at.  But, the strange shapes you are getting are from "point mapping".  Loft has to map points on each profile to points on the next profile in the sequence.  Fusion makes as good of a guess as possible for this mapping, but with complex profiles, that guess can be not what you want.  You can change this, however.  The white points in this image:

are draggable, and can be dragged to get the mapping you want.

If you share your design, I can illustrate with a screencast.

Jeff

[hubblebot]

Hi @jeff_strater, 

Thank you! I think I see what you mean about the point mapping, although I'm not sure how to move them. Here is a link to my project: http://a360.co/2iXmSTv

Do you think it would be worth the time to move all those points though, or should I try to model it following @TrippyLighting's tutorial suggestion? 

Thanks so much again!

[jeff_strater · Accepted solution]

You should always follow @TrippyLighting's recommendations!  In this case, yes, look at that tutorial, and start this in Sculpt mode - that will give you the most flexibility in changing the design as you go.  Trying to do this in the solid environment is probably not going to get great results.

My reason for posting was just to show everyone watching this thread how you can untangle a loft.  Here is a quick screencast of a loft between two of your profiles (I had problems with self-intersecting lofts with some of the others).  As you can tell, this is somewhat painful, and slow:

Jeff

[hubblebot]

Thanks so much to @TrippyLighting and @jeff_strater !

I am not following the tutorial exactly, but knowing that sculpt is a thing that exists is enough to get me started. 

[michael.k.jansen]

thanks for making this screencast Jeff.  I have been lofting boat hulls using this software now for a good 18 months, and have always struggled with getting a loft to "take" over a complex set of curves.  I had never realised ythe loft lines could be manipulated!

An now tonight I am on the verge of solving a tricky problem with a boat hull for a client that has had me tearing my hair out!

This method is, as you pointed out, not fast, and I am trying to work out of the loft lines can snap to points of vertecies (i think they do), but I now believe I can continue with the design using sketches and lofts without having to move to the sculpt environment.

cheers and thanks,

Mike