Extension from point

Hi all,

I’ve been getting to grips with the Mac version of Rhino over the past couple of weeks and I’m generally very impressed. My 3D drafting skills are rather rusty though, so please forgive me if this seems like a basic question.

In Autocad you have the ability to specify a new point based on an extension from a snap point. E.g.:

You hover over your “reference” point for a moment, then drag away in any direction along a plane to show the dashed extension line and distance/angle. And importantly, at this point, you can manually enter a length.

I find this functionality incredibly useful. Does an equivalent exist in Rhino? So far, looking through the docs, I’ve seen the relative coordinates functionality but that only seems to be relative to the previously drawn point, not a snap location.

Many thanks,


mmm… I’m not very familiar with AutoCAD, but the behaviour seems quite similar to SmartTrack in Rhino: http://docs.mcneel.com/rhino/5/help/en-us/commands/smarttrack.htm

It should be working with any command (move, extend, copy…)

Having re-read the SmartTrack documentation it is, in fact, exactly what I need. My problem was the OnOrtho guides weren’t coming up after activating a Smart Point because I had Near snaps enabled. Disable this and everything works as expected.

Thanks for your help.

Snaps in Rhino–a basic need used hundreds of times for every project–remain an area for dramatic improvement. Yes, they work. No, they are not quickly evoked.

Would love the ability to toggle the desired snap (most likely by using a unique keyboard command) if one wanted to temporarily prioritize it for any operation, including the one you describe.

The best (but still not ideal) solution I’ve found came from @jeff_hammond – to assign the pop up snap dialogue box to the middle mouse button. I’m on a mobile device, so I can’t assist if you need directions on setting this up, but maybe Jeff can post this again? ~Dave

Hi David - all the one-shot snaps work this way if I understand you - at least in Windows, I’ll have to check the Rhino for Mac implementation - that is, any snap invoked as a one shot like End, takes over from whatever is set in the Osnap box. Not sure if that is what you mean.


Yep. I’m aware of your method.

Proposed is a “more awesomer” suggestion. Desired is the ability to activate (or prioritize) the desired snap while in any routine WITHOUT having to open the entire snap window and toggle things on and off.

For example, while drawing a line amid existing geometry, one would be able to activate the desired snap by pressing an assigned key (and possibly holding it down) that temporarily prioritizes (and/or forces) only “end” , or another key for “midpoint”, intersection, etc. Optimally, one could change one’s mind in process by simply picking another key for another snap.

In this fashion, the cumbersome use of the snap window (actuating and needing to mouse to the desired checkboxes) could be minimized significantly, increasing productivity and workflow significantly.

Blame PowerCADD for spoiling me. I recall Maya permitting something similar, but much cruder. ~Dave

Hi David - please try this - set a pile of snaps in the OSnap box. Start some command that looks for a point, and type in say, ‘End’ or ‘Near’ and enter, or use an alias - note that the End or Near OSnap is now the only one active for this one pick - afterwards, all of the Osnap box snaps are back in action. This does work on Rhino for Mac, you do not need to interact with the Osnap control at all.


the command is:


it can be assigned to numerous gestures/aliases/etc.

if I’m using a mouse, it’s on a thumb button… on a trackpad, it’s three-finger-down-swipe.

Thanks for this, Pascal. It’s a step in the right direction (if I can get it to work), and one I was not aware of.

My reactions:

A) Full Command: Typing the full command, then Enter works as desired. Obviously, nobody wants to type the entire word “intersection”, so a one key alias would be really sweet, but…

B) Alias: One key for a snap (then apparently Enter) would perform as we’re describing. However, I might need some help here if it’s supposed to work, 'cause it’s horribly wonky for me. Here’s what I did to set this up. Did I get something wrong?
Rhinoceros > Aliases >

  • v = _EndSnap
  • x = _IntersectionSnap
  • c = _NearSnap
  • m = _MidpointSnap

While it works sometimes, I’m finding that there is some sort of voodoo involved in the timing between entering the key command and then Enter. Wait a bit too long and it seems to revert back to all the preselected snaps. Seems to work only if one hits the key then immediately (and I mean really immediately!) hits Enter.

Advice and/or your experiences with my examples?

(Experiments done using two intersecting lines in Version 5A854.)


@pascal: any insights to my last query?

Hi David - Aliases seem not to work well at all- but the snaps seems to work as expected if I type EndSnap (or just End, Mid, Near, Int works) I’ll dig into aliases that, just at a quick look seems to be messy right now.

OK, I see- it is possible to make two aliases with the same input keys, sort of temporarily- kind of cinfusing- If I get the aliases sorted out and correct, the process seems to work as expected. Still poking…


Thanks for checking into this @pascal. Wanted to confirm my efforts were done properly.

Ideally one could somehow enter one key for desired snap priorities (as you’ve probably realized). :smile: ~Dave