LDraw.org Discussion Forums
[LDCad] Rotation axis/ point finder - Printable Version

+- LDraw.org Discussion Forums (https://forums.ldraw.org)
+-- Forum: LDraw Programs (https://forums.ldraw.org/forum-7.html)
+--- Forum: LDraw Editors and Viewers (https://forums.ldraw.org/forum-11.html)
+--- Thread: [LDCad] Rotation axis/ point finder (/thread-27244.html)

Rotation axis/ point finder - Hilbert - 2023-04-01

Is there a way to quickly find and select rotation axes in LDCAD?

Right now I have to manually move the selection center to the preferred position then select the right axis and rotate the part.
If I later on another day with another model use the same part again I have again manually find the right position of the selection center,
which takes some time and is very repetitive and also quite fiddly. Is there some way to save this information of where the rotation axis is?
Especially for "natural" / "real life rotation axes" it would be convenient if there was a move selection center to rotation axis option (if selection is a single part).

"natural rotation axis" would be e.g. the connection (axis) of a hinge.


standard selection center (and rotation axes)
[Image: U5CJl.jpg]

moved selection center to "natural rotation axis"
[Image: U5Ir3.jpg]

Also what is the best and quickest way to do this if the selection is a submodel ?
I know I can again move the selection center manually - but most of the time I actually want to rotate the whole submodel
around the "natural rotation axis" of a part of the submodel.
I would like to set the selection center of the sub model just by clicking on that part (in nested mode? ) and then choose set to rotation axis and
then the selection center of that part becomes a selection center of the whole sub model and also setting the grid in the right way so choosing the part/submodel rotate option
rotates around the right axis-  in the main model space.

I wonder if a macro/script would be able to do this and if that could become fully part of LDCAD.

Because currently it takes way to long for me to rotate parts around commonly used axis (what I call "natural rotation axes")
and also whole groups/submodels/multiple bricks selections.

I hope it is understandable what I want.

RE: Rotation axis/ point finder - N. W. Perry - 2023-04-01

(2023-04-01, 17:48)Hilbert Wrote: Is there a way to quickly find and select rotation axes in LDCAD?

Right now I have to manually move the selection center to the preferred position then select the right axis and rotate the part.
If I later on another day with another model use the same part again I have again manually find the right position of the selection center,
which takes some time and is very repetitive and also quite fiddly. Is there some way to save this information of where the rotation axis is?
Especially for "natural" / "real life rotation axes" it would be convenient if there was a move selection center to rotation axis option (if selection is a single part).

"natural rotation axis" would be e.g. the connection (axis) of a hinge.


standard selection center (and rotation axes)
[Image: U5CJl.jpg]

moved selection center to "natural rotation axis"
[Image: U5Ir3.jpg]

Also what is the best and quickest way to do this if the selection is a submodel ?
I know I can again move the selection center manually - but most of the time I actually want to rotate the whole submodel
around the "natural rotation axis" of a part of the submodel.
I would like to set the selection center of the sub model just by clicking on that part (in nested mode? ) and then choose set to rotation axis and
then the selection center of that part becomes a selection center of the whole sub model and also setting the grid in the right way so choosing the part/submodel rotate option
rotates around the right axis-  in the main model space.

I wonder if a macro/script would be able to do this and if that could become fully part of LDCAD.

Because currently it takes way to long for me to rotate parts around commonly used axis (what I call "natural rotation axes")
and also whole groups/submodels/multiple bricks selections.

I hope it is understandable what I want.

An easy workaround is to use groups. You could group even a single part, then change the selection center and the "Set group center" under the Grouping menu. Doesn't help you in multiple models, but at least within one model it keeps the center of that part consistent.

In your hinge example, in my opinion the solution is in the parts authoring itself—the part should have had its origin set to the rotation point. But it wasn't, so…

For submodels, I use the same principle: set the origin of the submodel to a likely rotation point.

Finally (and I had frankly forgotten about this), in the Selection Center context menu, you can jump the selection center to the different snap positions of a part (assuming it had snap info), which is likely to include a natural rotation axis.

RE: Rotation axis/ point finder - Hilbert - 2023-04-02

(2023-04-01, 22:59)N. W. Perry Wrote: An easy workaround is to use groups. You could group even a single part, then change the selection center and the "Set group center" under the Grouping menu. Doesn't help you in multiple models, but at least within one model it keeps the center of that part consistent.

For submodels, I use the same principle: set the origin of the submodel to a likely rotation point.

I have done similar things works nicely.

Quote:Finally (and I had frankly forgotten about this), in the Selection Center context menu, you can jump the selection center to the different snap positions of a part (assuming it had snap info), which is likely to include a natural rotation axis.

This is exactly what I was thinking about. Using part snapping info to find the right selection center point in an easy way
and then using rel grid alignment (if not already correctly aligned) for getting the right axis.

Thanks for pointing this out to me. I did not find it in the current version (LDCad 1.6d V2) but then I tried the latest alpha (1.7 Alpha 2a) and there this brand new option was there.
Very big thanks to Roland Melkert for implementing these very useful options (in the Selection Center). Saved my day and it is a game changer for me!

RE: Rotation axis/ point finder - Paweł Turalski - 2023-04-02

Let's do it with your hinge parts

You have to take some helper part. For this connection, in "Search" tab, find a bar part. I used Bar 3L (87994), but you can use longer too

.jpg   Clipboard01.jpg (Size: 13.86 KB / Downloads: 36)

Put it into the hinge point. It is better to paint it on unusual color, here I used dark pink, but the choice is yours
   

This is optional and does not change anything, but you can move it like that
   

Now select the bar
   

Then hold the ctrl button... 
   

...and select the hinge top
   

Press R and rotate your camera. Now you can rotate the hinge top as you wish
   

You can select more parts or/and submodels if you need. All you need to remember is that helper part MUST be selected first, then other parts that will be rotated