Alt + copy seems to be broken

In the 1.0.004 build, the alt+drag to copy keystroke seems to be broken.

not every time though. selectively, it seems to work. I haven’t found a pattern of when it will work and not.

it works unfortunately only after you press alt twice short in a row. a strange behaviour which i did not understand yet. good that you ask that and i hope it will be changed to pressing alt only once.

oh just saw that you have grasshopper in tag did not see that at first sorry, but trying out grasshopper i see that it works actually every time. and there it works with pressing alt only once…

good to know, it may very well be an artifact within my file. it seems to be working when I select only one object pretty reliably but if I select select two or more objects at once, the copy doesn’t work predictably.

maybe it has trouble computing the duplication, just a wild speculation of course since grasshopper on mac does not run as smooth as on windows. you could share a part of your definition if you want somebody to have a look.

The alt+drag copy “bug” has been around for a long time (V4?) and affects Windows Rhino as well. It stems from the fact that that holding down Alt is also used to toggle object snaps, thus the system has to figure out the intention of the user every time - i.e. how long the Alt key is held down before the system counts it as continuous (thus an osnap enable/disable request) or a “press and release” with an object being dragged, indicating a copy is wanted.

IMO, the only reliable way to make sure you copy is to start tapping the Alt key after you start dragging your object(s) until the little “+” sign shows up on the screen, which means the system has understood you want a copy. You tap as many times as necessary until the plus sign shows up. No “+”, no copy…


since this toggle is only activated during a command i see no problem in keeping alt copy for drag copying objects, alt does not toggle anything without command running, at least in mac rhino.

@dan can we have a fix for this?

Well it’s not actually, that’s the problem. You can also use Alt to toggle osnaps during dragging when no command is active…


what for? nobody can activate any of those while having the mouse button clicked and holding an object. pressing alt toggles it yes but what shall i do with a blinking window full of osnaps when i cant press them. maybe thats different in the windows version, do the objects keep dragged when pressing alt and letting the button go?

holding the object with the mouse and typing the alternative osnaps with the other hand works though, which is without autocomplete a complete disaster and anyway i wonder if osnaps make sense here at all.

precise osnaps can be used during the move or the copy command and make rather sense there, but sure not during a quick drag and drop or alt copy which mostly is for simple layout tasks like distributing a few trees, stars or hearts or further iterations, but not for precise modeling i believe.

but back to alt copy, this should be fixed. the prompt window showing while dragging an object also declares that tapping alt should work and it does not say double tap alt :slight_smile:


You don’t use snap-dragging then… Too bad, it’s quite a time saver.


i do, but sure not with alternative osnaps.

I got the feeling this topic was not started about alternative osnaps… It was started about tapping Alt not consistently engaging the copy function. I explained why this might be buggy.


the actual topic is about grasshopper, just to point that out once more. you explained why rhino alt copy is supposed to be buggy which it is not, it simply is not handled or lets say thought through and executed properly in the software.

we can open a new thread if you insist but the topic name is as misguiding as it seems sure also usable to discuss the rhino alt copy issue i hope.

hmm. single tap works fine for me.

fwiw, there’s another pre-click function tied to alt… that being, you can hold down alt while the cursor is over an object then do a window select without dragging the object.

also, it’s used for zoom (to center) in conjunction with right-mouse-button.

lots of stuff on alt/option key… arguably, too much stuff but maybe a little late to be switching it all around now.

re: grasshopper.
again, alt/copy works ok for me… with one component or multiple components.

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yup, i didnt realize that it actually works only on release, tapping is obviously something different to pressing so most probably my bad :blush: but also holding it longer and letting go does not work reliable which lead me to believe i have to press twice. in grasshopper it works already on click, rhino could at least work the same here. any other software i know of including the macos finder lets one duplicate the object pressing alt before or after the dragging process has started.

i believe thats cmd + RMB

yeah, for mac users, the behavior in Rhino regarding alt is weird…
i think i remember a discussion about this a few years ago but i’ve since gotten used to it.

command+RMB will zoom to cursor… alt+RMB will zoom to center (generically(?) zoom the viewport regardless of where the cursor is)

well i hope that dan or anybody might have a look into this thread considering to issue a clean up.

ah yes i didnt notice, i tried in the orthogonal projections where it didnt work not sure where to use that though?

i don’t use it and also am not sure of a situation where i’d need that type of zoom instead of zooming to cursor…

I think this behavior is a bit weird too. However, I’ve gotten used to it (but I don’t do a ton of modeling any more). For me, this is one of those “Well, Rhino for Windows and Rhino for Mac are a bit weird, but consistently weird” issues.

in grasshopper it works already on click, rhino could at least work the same here.

I’m not certain what “on click” means here. In Grasshopper, I always have to be careful not to hold alt first before I click the component, otherwise I’ll trigger the “Moses” separation functionality.


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i meant that it works while already pushing the alt button in, contrary to rhino itself where the button has to be released completely and very fast, to trigger the plus to show.


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