WIP: connections command

Nice to see that this is being developed!
About the naming: for me it would make more sense to call it relations or constraints.

for the UI, it would be convenient to have the info visible at the selected entity. For example in SW it is done this way:

where you see if objects are fully constrained/defined (black) or have degrees of freedom (blue) and at their connection points, you get icons to indicate the relation once selecting the item.
I think this makes more sense: You want to see the relation of a certain item, not select a relation and see which item is affected as it is done now.

If I select an arc to make it tangent, I seem to only make it tangent to lines, not to curves or other arcs.
Same goes for perpendicular.

It would be nice to have vertical and horizontal constraints for lines between nurbs curve points too:


I agree!

But. I’m wondering: When do you want to receive feedback on this, since it seems to be still in development? And if already now, perhaps we could get some info on how it’s intended to be used right now and what it’s current limitations are and what you’re going for. Right now I don’t know if something is missing because it doesn’t work yet or if it is not intended on being developed.


Additionally: For me to make this tool useful, these would be welcome:

  • add dimensions to lines/arcs/controlpoints
  • add positional, tangency and curvature relations between end points of lines, curves and arcs
  • add relations between dimensions, for ex. make line_01 length equal to line_02 + line_03
  • add other relations like: concentric, coradial
  • once the tool is active, and you select on or more entities, give a relevant popup that shows the possible relations that can be added. For example, if two lines are selected, and touch at their endpoints, it could pop-up, colinear and perpendicular.

Hoi -

So far, the internal discussion says that it’s too early to make an announcement and ask for feedback. That shouldn’t stop you from providing feedback at this point! It will all be read and taken into consideration.

For me, personally, I’d like to see the bigger picture here. I started working with different MCAD applications in the '90s and know how, and why, constraints are used in those. I’d rather not “constrain” the conversation by asking very specific questions… How do you see this applied to Rhino?


For me personally it will be more of a nice to have feature when I need it, a bit like how History works. I work mostly with one-offs and I’m not sure if I’ll be using it a lot as it also takes a lot of time to set up a good useful parametric model that doesn’t break.
That being said, I can see some useful applications with dynamic blocks if it’s easy to create a library of customizable parts. But in order to do that I guess one would need to work with the concept of sketches like you have in other software and have other commands linked to those sketches. Not sure how that would look like/work in Rhino

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This feature is still very much a WIP which is why no announcement has made yet. When that occurs there will be examples and hopefully things will be a bit clearer. Do feel free to experiment and give feedback. I do like the idea of visual feedback for constrained objects. I opened an issue for that. The arc tangencies do need improved but @pascal beat you to the punch on creating an issue.

The widget button for length and angle constraints in the connections panel should give something similar. I am aware of a few issues with them though.

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RH-67391 is fixed in the latest WIP

Very interesting!


The feature is still under development but it has been announced here

Hi @Joshua_Kennedy,
Sketch constraint is a dream coming real for me. It’s the only feature I’m envy of parametric.

My consideration is about the interface. I saw your video and having the constraint as a panel like an option make them more complex to use.

I can understand that I need to define a sketch to make it working but why aren’t all closed crvs directly converted into sketches? This would speed up the process a lot. Then, if you really need an open sketch you can decide to make it explicitly.

The other things is why the most wanted, need, useful, icons (the constraint them self) are hidden inside a panel and then under a “shy” +.
Why the constraint aren’t a proper toolbar? Like any other rhino tool.

3rd, like Gijs showed you, the icon should be visible directly next to the associated geometry, and should work as button or as delete function.

4th, wish I can constraint a length or an angle by adding a dimensions or the constraint can create a dimension automatically.

Hope this helps making this better.

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That’s getting worked on. This issue is open here. The UI for Rhino 8 is having a large amount of work being done and the toolbar is sidelined until it stabilizes a bit more. I do agree with you that it is a lot of extra clicks currently.

I think this is a bit heavy-handed for users who may not be doing any work with constraints. I’ll keep it in consideration though. I think the more general idea is getting setup takes a bit too long currently. This is something that we’ve been discussing and working on quite a bit.

We are working on making things more interactive in the viewport. As I get a few more issues with this knocked out I’ll make another video showing some improvements.

Thanks for the feedback! I think you bring up some good points.