Persistent pivot points

[rjacobs1969]

The pivot point function is great to test hinges and clearance between rotating parts. however it would be very useful is a pivot point can be persistent to an object, so when designing an hinged feature I can repeatedly check without having to redo the pivot point every time I had to select another object to adjust it position or size

[henmedia]

Thanks, @rjacobs1969, that makes sense for hinges. Today the pivot point belongs to the current selection and is cleared when you select something else, so you have to set it again.

What I'd build: a pivot point that stays with one body. You set it once, select other objects to adjust them, and when you come back to that body the pivot is still there (and moves with the body). It would be saved in the project and shown as a small marker, and the same button clears it. With several bodies selected it would behave as it does now.

[prmod3d]

Yes, I would appreciate this mod as well! Also, it seems like the pivot points can only be set at the centers of an object (or group). Would it be possible to move the pivot points to other locations, via the mouse or cursor key nudging?

[henmedia]

Thanks for the vote, @prmod3d. Today the pivot sits where you click: on a flat face it is the centre of that face, on a curved surface it is the exact point you clicked, and without one the selection turns about its own centre. Once it is set, it cannot be moved, neither with the mouse nor with the arrow keys; you set it again.

Both of your ideas fit well with the pivot that stays with a body: dragging the marker (snapping to corners and edge midpoints would help there) and nudging it with the arrow keys or typing its coordinates. I'll note them on the idea. Nothing is promised or dated yet.

What would you use it for? For example a hinge pin at a corner of a part, where there is no face centre to click? That helps me decide which of the two matters more.

[prmod3d]

I'm currently working on a project (in Tinkercad) which uses a double cantilevered articulated arm. There are seven rotational points of motion I need to keep aligned while modelling the design. As I make changes (especially with regard to arm clearances) I need to be able to rotate a part to ensure it doesn't interfere with anything else -- and often it's more convenient to quickly do this without first needing to group the arm with a post which may be the identifying pivot point, or having to accurately replicate the pivot point each time.

Of course Tinkercad doesn't offer user-defined rotation at all (which is very frustrating!) and I had to develop some tedious workarounds. In fact, searching for an easy-to-use alternative to Tinkercad which allowed for defined rotation points is how I discovered the Layerling project... and seeing all the other features (especially chamfers, fillets, and saving projects outside the cloud) was the icing on the cake that won me over!

I've since been discovering all sorts of Layerling features I didn't know I needed until I saw them! Now if only there were some way to move over the 80+ design projects I have on Tinkercad...

[henmedia]

That helps a lot, @prmod3d, and thank you for the kind words. Seven joints on one arm is exactly what a pivot that stays with its body is for: you set each joint once, and then you rotate any part of the arm about its own joint, without grouping it with a post or placing the pivot again.

About your Tinkercad designs: I'm afraid there is no way to carry them over as they are. Tinkercad only exports the finished shape (STL, OBJ, SVG), not the editable objects, holes and groups. Such a file comes into layerling as one solid mesh that you can move, rotate, scale, cut and combine, but not edit shape by shape any more. For parts you only need to keep, or to fit new things to, that is often enough.

One question for the pivot: would one pivot per body be enough for your arm, or does a body sometimes need more than one joint?

[prmod3d]

Yeah, I know all about the limitations of Tinkerd's export options. I knew when I started using it that one day I'd have to abandon all my designs because they don't allow a way to save projects in a fully editable format. Will not make that mistake again!

For my current purposes, one pivot point per body is sufficient. I was trying to think of a situation where more than one would be useful, and could only imagine it being quite confusing!

[henmedia]

Thanks, @prmod3d and @rjacobs1969 - one pivot per body it is, and it's built:

• With one body selected, the pivot you set now stays with that body. Select other parts, come back, and it is still there; it moves, turns and scales with the body, is saved in the project, and Undo takes it back.
• The same button removes it, and so does Remove under Position.
• Under Position you can also type the pivot's X, Y and Z, or nudge it with the sliders (arrow keys work on a focused slider) - handy for a hinge pin at a corner.
• With several bodies selected the pivot works as before.

Dragging the pivot marker with the mouse is not in yet. It will be in the next release.

[henmedia]

It is out in 1.47.0, @rjacobs1969 and @prmod3d: with one body selected the pivot stays with that body; it moves, turns and scales with it, is saved in the project, and its X, Y and Z can be typed under Position. Here is the section.

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[prmod3d]

Excellent. I tested and it works great. Am looking forward to moving the pivot marker with the mouse in an upcoming release, as this will likely be more intuitive for general placement, with precision nudging via the Properties section.

[henmedia]

@prmod3d @rjacobs1969, dragging the pivot is in 1.51.0: grab the red pivot marker and move it. It slides over the surface of the bodies and snaps to corners, edge midpoints and edges, so a hinge pin lands exactly on a corner. Where you let go, it is set as before - kept with the body, saved, and Undo takes it back. Typing X, Y and Z under Position still works for fine adjustments. Here is how it works.

[prmod3d]

Superb. Just tested and it works great. Thanks!