Loft using hullcurves

[robin.jonsson.4276]

I want to create a Loft between a triangle and a square. But I need to be able to control the silluette of Hull_XY and Hull_ZY, also be able to change the angle of the profile_bottom. I have tried using Loft and Sweep in PartDesign WB but they don't allow enough control. CurvedShapes WB gives mix results (most of the times it produces lines that doesn't intersect). I have tried to use the same amount of segments in the profile, I tried opened and closed hulls, reversing and rotating faces, separating Hulls. But I never get a good result. In the attached file I have simplified the problem.
(I have had this problem for over one year, it really haunts me)

OS: Windows 10 Version 2009
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24276 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: a88db11e0a908f6e38f92bfc5187b13ebe470438
Python version: 3.8.6+
Qt version: 5.15.1
Coin version: 4.0.1
OCC version: 7.5.0
Locale: Swedish/Sweden (sv_SE)

[Shalmeneser]

It will be difficult to loft a triangle with a square. And the planes are not parallel.
What is the purpose of Hulls ?

If you explain your goal, perhaps other method can be found.

[robin.jonsson.4276]

t will be difficult to loft a triangle with a square. And the planes are not parallel.
What is the purpose of Hulls ?

If you explain your goal, perhaps other method can be found.

Hi, thank you for your reply. I'm trying to create the ear of a manchu bow (the utmost point of a bow). Historically they are triangles at the knee and rectangles at the nock. I want to test different profiles of the ear to reduce weight and optimize durability. Therefore I need to control the hulls in two planes. I could probably make profile_top and profile_bottom parallel then remove a wedge at the bottom when it's done, so parallel isn't super important. When FEM testing and 3d printing destruction tests are done I want to manufacture a mold in aluminum.

[Pauvres_honteux]

Sorry to be the "bringer of pain"! (was that Battle beast? )
The function "assign a point on section1 to another point /points on section2" is not implemented or even asked for (feature requested) yet. On top of that the direction of each section can not yet be altered, it also lacks a feature request. And just to really rub it in, we lack the possibility to set start and/or end tangency conditions for multi section surfaces.

However, the light in the tunnel (it's not a train) is that we can fix the request part of it. But we would need someone to dig into it, unfortunately so far it seems to be quite tough to dig that deep, even for our most decorated programmers.

But maybe you can do programming and have the energy to do so? Or someone you know would be intrested? Perhaps asking around among your chummies would give something?

The closest you can get today is via the Curves workbench by Chris_G.

[Shalmeneser]

PartDesign doesn't seem to be the right workbench. PartDesign_AdditivePipe is too rough.
Try Surface / Curves / Silk?

You'll need Image_Module to put your different curves at the right place and copy forms.

[robin.jonsson.4276]

Sorry to be the "bringer of pain"! (was that Battle beast? )
The function "assign a point on section1 to another point /points on section2" is not implemented or even asked for (feature requested) yet. On top of that the direction of each section can not yet be altered, it also lacks a feature request. And just to really rub it in, we lack the possibility to set start and/or end tangency conditions for multi section surfaces.

However, the light in the tunnel (it's not a train) is that we can fix the request part of it. But we would need someone to dig into it, unfortunately so far it seems to be quite tough to dig that deep, even for our most decorated programmers.

But maybe you can do programming and have the energy to do so? Or someone you know would be intrested? Perhaps asking around among your chummies would give something?

The closest you can get today is via the Curves workbench by Chris_G.

When this is finished, it will be my magnum opus! I lack any programming skills, but I might have somewhat solved it with Curves workbench. I also used a boolean cut and some trigonometry to get my desired angle at the bottom. Still need to tweak it a bit more to get the square shape closer to the triangle.

PartDesign doesn't seem to be the right workbench. PartDesign_AdditivePipe is too rough.
Try Surface / Curves / Silk?

You'll need Image_Module to put your different curves at the right place and copy forms.

Copy forms and Curves Workbench seems to be the answer. The profiles had same amount of edges, but different positions (clockwise vs anticlockwise + starting point). Therefore it twisted and inverted itself.

Thank you for all of the help