Hi Burr,

> can you see limitations that are there, that cant be easily
> overcome, because of the initial design and thought process?

Yup, definitely - and it took quite a bit of work to eliminate many of these for MoI's design.

One of the big ones is that Rhino depends mostly on a command being run first to set the context of how selection will work.

Like for instance in Rhino if you want to fillet the edges of a solid, you run the "FilletEdge" command first, then that prompts you to select edges. Then at that point if you do simple left-clicks it will select edges. So your selection clicks behave differently if you do them before you run the command as compared to while you are inside of the command.

This kind of made sense from a development point of view, since it meant each command can be pretty streamlined since each command is more narrowly focused. That's why I went in this direction, it kind of seemed at the time to be a simplifying path.

But overall it ends up causing problems from a UI point of view because it means it can be hard to combine multiple things into just one command, so instead there are a whole lot of separate commands, which means a whole lot of menu items, a whole lot of toolbar buttons, etc...

For example in Rhino there are 4 commands for filleting tasks: Fillet (for filleting 2 curves like 2 lines), FilletSrf, FilletEdge, and FilletCorners (corners of a polyline). In MoI these are all handled by one Fillet command instead, so that enables quite a lot of reduction of UI.

Some other workflow problems in Rhino are hard to get rid of because I set up some actions to be primarily compatible with AutoCAD so they kind of follow a different pattern. This is the reason for example why in Rhino the "Trim" command works kind of in the reverse way from "Split" - for Split you select the object that will be cut, and then cutting objects but for Trim you do it in the reverse order. This is because Trim was set up to be compatible to AutoCAD. Being compatible with AutoCAD is not 100% bad though, I mean for AutoCAD users it is great, and since McNeel is very much steeped in AutoCAD stuff from being a long time dealer, it was a good fit for the company there to be focused on that. But it definitely had some long term consequences as well that are hard to get rid of.

There are quite a number of these kinds of things, like another one in Rhino is that before a command is run you can't select a curve that has points turned on, you can only select its points and not the curve itself. I was worried about potential ambiguity between full object and point selection, but that turned out to be a mistake...

- Michael