Logic behind Smash command ? Different outputs based on surface normal direction

Just trying to understand the logic and behavior of the Smash command.

I am smashing a bunch of double curved surfaces, here is one of them ( I am attaching a top view to show the geometry pattern mapped on the surface, the 3d view is irrelevant in this case):

What I discovered is that following the orientation of the surface, the smashed output is oriented/mirrored differently… (this makes sense but perhaps a small note regarding this matter in the command help would be nice for the general public).

However, and this is the part I don’t get ! Regardless of the surface orientation, Rhino mirrors the output following the X axis.


The correct (or the smashed output I am searching for is the following) …

I noticed also, sometimes depending on where I click on the surface, the output orientation is different.

Any tip or clarification would be much appreciated ! ??

Thanks !

Hello - please post an example object.


@pascal sure thing, here is a file with the object above.

Looking forward to your explanation.
2021_05_14_Object_For_Smash_Command_Clarification.3dm (1.6 MB)

Hello - the surface normal is mapped to Z on Smash. It looks to me like the orientation is 180 degrees from what you want, and not mirrored.


Hello @pascal
Thank you for looking at the file.

The surface normal mapped to Z on Smash command, that I figured out. However, As you see from the screen shots above, the result IS mirrored ! This happens unexpectedly from one surface to another.

That is the reason I asked for more details on the Smash commands, or perhaps should I look at the command script itself ? Any ideas where I can access this ?


Hi Ghali - if I mark one edge and then flip the surface so the up side is up on Smash, then I get this: