topic Re: Problem with a complex Loft Shape in Fusion Design, Validate & Document Forum

Problem with a complex Loft Shape

ianhughes7UFVF — Fri, 25 Dec 2020 13:08:19 GMT

I am reworking an old project but struggling to recreate this complex shape. I four different profiles to join and a loft didn't work as per my normal attempts so I used a patch, but I cannot thicken the result 6mm that I need. Here is where I am at:

Here is the error when I try to thicken it:

Any help to move forward on this would be great as I have been stuck on this for weeks. Restarting the project over and over and arriving at the same problem.

I have attached the fusion file for you to look at.

Regards

Ian

Re: Problem with a complex Loft Shape

Beyondforce — Fri, 25 Dec 2020 19:50:32 GMT

@ianhughes7UFVF ,

Do the thicken in the end. not now!

If that won't work, then I'll help you.

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Fri, 25 Dec 2020 22:56:55 GMT

Its been the problem that I have created the rest and then returned to that area and tried to thicken it and it hasn't worked which is why I was going to see about sorting it now. It actually needs to be mirrored. The whole shape would be good to do in one big loft but I haven't been able to achieve that. The circle at the top seems to make it a very difficult thing to do.

This is the shape I am trying to create:

Would you know why I could only make that panel in a patch and not a loft. A loft is what I am use to.

But if you have time to help me get that part working it probably will help me with the rest.

Regards Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Fri, 25 Dec 2020 23:46:25 GMT

Loft the half front view to the half side view, and horizontal rails, then shell 6mm.

Might help....

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 00:06:21 GMT

Amazing Dave. Once again, achieved something so simply.

I am totally impressed.

One question. The sides are a little out of shape. They need to be circles. Is that something hard to adjust.

Regards

Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 00:13:04 GMT

That depends on if you are following the canvass or not,

You can build circular object outside the main body.

Short answer is not hard, make / edit the rails go where you want them. Project the small circle into the rail sketch, and make the spline coincident to it.

Might help...

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 00:25:20 GMT

Ok, thanks. I will have a look.

I appreciate your help once again.

Regards

Ian

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 06:07:39 GMT

I am trying to recreate what you did Dave.

How did you create this curve?

It looks like a spline but not sure how to recreate it?

Regards

Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 07:29:26 GMT

Project > Intersect the 3 sketch articles that I need, and join the purple dots with a single spline.

Edit Sketch 14, Project > Intersect the circle from sketch 4. Select the Spline, right click, Select insert spline point, click on the spline near the new purple point, then make that new point coincident with the new purple point.

I made Plane 8 as an Offset plane, at point 3, in my first pic. Black dots were purple before I draw the spline,

spline handles constrained horizontal / vertical.

But the round arm hole, if absulutely required, will mean the loft and sketch one have to be modified, and you will lose the top arc rail. Geometry with that top arc rail is not possible, due to tangent rail error and a self intersection.

Might help....

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 07:23:03 GMT

Sorry, I am having trouble here. I cleaned up what I did but I am having trouble trying to get the rails to work right and the profiles to extend like you did.

This is what happens:

Sorry to be so dimwitted.

Regards Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 07:43:25 GMT

Your Sketch 1 is not the same as mine, you need the top construction line to be normal will be Profile 2.

You have to untick, chain select, before collecting the rails.

Your second profile, should be the my red shading part on the other side. Sketch 3 is a rail, one curve.

Might help.....

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 08:29:21 GMT

I made those changes and still doesn't work?

Sorry about this.

Still not sure what I am doing wrong.

Regards Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 09:10:33 GMT

Wrong profile 2.

Well fusion just does not play well with duplicate articles that overlay themselves, and I don't expect to find them, when Fusion does play up, I normally find them. They did not cause me drama in my file, but they were there.

Your sketch 1, delete the small arcs, and the second ellipse.

Make the centreline normal, and use these two half view sketches for the profiles,

Sketch 3 and Sketch 13 for rails.

Might help.....

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 09:49:18 GMT

I did that, but it complains the rail is not smooth and wont allow it to use the rails?

Did you have that problem with my drawing?

Regards

Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 10:23:44 GMT

Yes and No, I have deleted what I said, I needed to, made the vertical centre line - normal / solid.

Then the Loft worked first go.

How can a rail curve that is one arc, and a spline curve that is one spline not be smooth? Very careful selections and

This loft worked in your file after my edits.

But -

This Loft will not give you the round circle hole for the arm, it is the first version.

To do the round circle hole for the arm, is a whole different set of sketch preparations. That second version will not let us have a round neck opening, by a little bit off, but does give me the round arm socket in 2 lofts.

Might help....

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 10:40:31 GMT

That worked.

I cleaned up that center line in Sketch 1 and unselected the chain in the loft.
Sorry to have taken so much of your time to get this right.

But thank you.

Regards

Ian

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 10:50:50 GMT

I can see what you mean about the holes on the side. They are for leg hinge pivots so they need to be round.

Is it hard to do define what else I need to get them to be round?

Regards

Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sat, 26 Dec 2020 11:20:33 GMT

This one is the latest - version 2, one I prepared earlier, in case it has to be round.

Loft your geometry, will give round arm holes, or round neck hole, but you can not have Both.

The Sketch 3 rail will be rejected in the new version, with Rail can not be tangent error, and will not preview without a yellow shading.

However round arm, and sort of round neck, covered by another part of the model, would be OK, if it were me.

This model had so many changes to Sketch 1 I just replaced it with Sketch 15, Hide sketch 1.

Loft your 2 arm circles, with 3 rails, from sketch 14 and 15.

Make a dummy extrusion for half of Sketch 6. (Same profile as before, but getting rid of the creases)

Hide all sketches, and new loft from face of Loft 1, to the dummy extrusion face, make both sides Tangent condition.

unhide sketch 14 and 15, and pick the same three rails again. Perfect.

Might help...

My file is same name, so change the name when downloading to make comparisons, or just overwrite the old one, now that your file works, for version 1. Can't be sure the file is up to date, I did save over it, but has old time stamp on it.

Re: Problem with a complex Loft Shape

ianhughes7UFVF — Sat, 26 Dec 2020 12:33:21 GMT

Thanks for the second option. Unfortunately I don't make it easy for myself, because the original design of the prop requires the top circle to be correct and those side circles to be correct. I realize you said we carn't have both, but I need both to be circles.

I tried this, I added circle extruded sides in but, the ridges will be problems:

So are you sure there is no way to get both top and side circles correct with the loft?

Regards

Ian

Re: Problem with a complex Loft Shape

davebYYPCU — Sun, 27 Dec 2020 01:11:24 GMT

And Version 3.

You can get both circles, if you abandon Sketch 7.

That said, Fusion is so finicky that mirrors and split bodies have to be a certain order, to have a top flat circle face, and the tube cut for the leg's hole, are all fussy.

Top surface is a Patch, 3 edges and two internal rails, (top and side arcs)

Lower surface is Loft with 2 edges and 2 rails, but only 1 edge / Rail is allowing the Tangent condition, 2 makes the loft fail.

Might help....