loft function problem

[lukas.ehebruster]

Hi Guys, i am currently trying to build this specific form with fusion360 as you can see in the video attached. I am using the loft function and afterwards i want to use the dots to turn the axis of the loft. But when i hit OK, suddenly the form jumps back to a normal loft without twist. Can somebody tell me what i am doing wrong?

[g-andresen]

Hi,

Please share the file.

File > export > save as f3d on local drive  > attach it to the next post.

günther

[Bunga777]

I tried to make a mimic of a similar shape, but the symptoms occur as you say.

Could it be that some shapes are intentionally not allowed to shift points?

[davebYYPCU]

Your selections are driving factors, not the mapping handles.  You need 3 profiles to do that.

You need the middle sketch to be 2nd profile of the desired shape without moving mapping handles.

Might help....

[Bunga777]

I see!

I tried it, but the result was still the same.

Is the shape of this profile the problem?

[TrippyLighting]

@davebYYPCU what the OP is trying to achieve should work by just moving the mapping handles. This is a bug!

[davebYYPCU]

@Bunga777 Try an ellipse there.  Same profile is not going to twist.

@TrippyLighting Mapping handles and a centre line, never tried it.

Might help....

[lukas.ehebruster]

Hello again, so the thing is; someone created a tutorial for me to show me how to get this form and i tried to rebuild it or rather adjust the dimensions. If I build it on my own, the problem described in the first thread appears. If I use his file and adjust the dimensions in the sketch, the whole program crashes. Please see the files attached. previous file is the tutorial file.

[TrippyLighting]

I've not tried to reproduce that crash. No software should ever crash!

However, I am not surprised that Fusion 360 crashes.

Mirroring a fit point spline is not a good idea. Using a 3D sketch when not needed is not a good idea. Not properly dimensioning and constraining a sketch is not a good idea.

You'll find that when you create a more solid foundation for your designs you won't run into these problems 😉

[TrippyLighting]

The reason you can not drag the handles in your design as freely as in the initial design is because you have sharp corners in your loft profiles, where as the initial design has round corners. I suggest, however, not to follow that initial tutorial, because the person creating it doesn't really know what he's doing either 😉

First you need to decide how much of a twist you actually want. Then you can get better control over the shape not using a center rail. You could try a 3rd loft profile.  One or more rails might be a good option.

In this example I used two rails to have better control  over the loft: