Defining constants

Replies to This Discussion

Permalink Reply by David Rutten on January 12, 2012 at 3:26pm

This is the reason why Expressions were busted in 0.8.0064. I started adding plumbing for constants but it was half-baked.

There are several major problems with the notion of constants, and until I have at least a workable answer for each one I can't finish and expose this feature:

1. Recursive/Cyclical relationships. It's quite easy to detect when wires form a loop. Not so easy with constants which are defined in one place and then used in any number of other places.
2. Updates. It's very difficult to figure out which expressions become 'stale' when the value of a constant changes.
3. Scalability. The basic idea of the Grasshopper data structure (trees, as they are lovingly known) is that you can take any algorithm and apply it to a larger amount of data. At least in principle this is always possible. If you can make a line between two points, you should be able to create a whole bunch of lines between a whole bunch of points. Constants would break this rule. Basically it means that one should be able to define not just one constant, but a whole collection of constants and any expression using them needs to automatically figure out which item in the collection is the relevant one.

(2) is the biggest problem and I don't see any half-way decent solution yet. 

--

David Rutten

david@mcneel.com

Poprad, Slovakia