Lofting from a complex surface

[metd01567]

I’ve successfully created this body by lofting from a stack of 2D sketch profiles with guide rails defined in a separate 3D sketch.  Note the last loft profile is a single point.  This has a flat back surface with a single face (not shown).  This body is used to cut a larger flat surface, the edges taper down until they are tangent with the larger flat plane.

I want to drape the body over the intersection of two planes, with a filet at their intersection. I’ve attached the design.  Because the fillet creates a middle face, each stage of the loft is broken into three profiles.  Which doesn’t  work.  Using three separate lofts joining together, I managed this (without rails):

I tried using rails, but they aren’t right and weren’t accepted by the loft command.  Plus I suspect there will be discontinuities even with good guide rails.

My goal is to achieve a draped body with form similar what was achieved with flat sketch profiles.

[johnsonshiue]

Hi! I am still trying to understand the design intent here. But based on what I see in the model, I am not sure the 4 separate Loft operations will yield a satisfying result. I guess you may need to use a combination of Loft and Tspline so that you may get smooth transition between geometry.

Many thanks!

[metd01567]

I’ve attached the design that created the first screen shot.  Those 4 faces are the result of a single loft with 4 guide rails.

I believe I can’t loft from multiple contiguous profiles, like I’ve got with the new draped surface.  Could someone confirm that for me?

I’m going to try another way, using a single 2D sketch profile and guide rails. It will be too big, but I can cut it with my top surface to get what I want.  Maybe.

[TrippyLighting]

Please create a paper/pencil sketch of what you want the final shape to look like. Your explanations leave too much room for interpretation make absolutely no sense to me 😉

My guess is that you won't get there with solid lofting.

[metd01567]

A nine year old would do better hand drawings than me.  Here are a couple of cross sections that might get the idea across.  First, here's a screenshot from FlatForumTestShape (attached with my second post), which works as I want.  The lighter left body is the actual end result.  I've cut a flat plane with the body on the right (which I've flipped to show in cross section).  I am willing to loft directly into the flat surface if it helps, but I started this thinking plug and mold.

Now I have to cut an angled surface, which I tried to do in the design attached to my first post.  The start profile sketch is shown, spanning the filet between the two flat surfaces.  The sketch is referenced to the right hand flat surface.

So by "draped", I mean the plug with be bent along the filet, while retaining the basic shape.

[metd01567]

I rotated the loft direction 90 degrees in my flat example, and did it as a surface loft, using split body to do the cut.  Now the loft is point to point, you can see the path of the loft as a line in the screenshot below. 

It’s a little hard to get a screenshot of the surface, here’s a try.  I only moved the cutting surface this time, I didn’t flip it.  So it’s concave in this picture.

It works flat, it should work over a bent surface in theory.  But now I’ve got create all the guides properly.

[davebYYPCU · Accepted solution]

Use Sheetmetal Fold / Unfold, but the end result may not be what you wish for.

Might help….

[metd01567]

Thanks, that will do what I want once I incorporate it into the main design.  I haven't studied the sheet metal commands, it looks like I should.