Why define circles by radius instead of diameter?

[ipsod]

When dealing with mechanical parts, it's easier (possible) to measure diameter. You don't really see blueprints with radius specified - it's always diameter. So, why use radius in this program that's mostly used to make mechanical drawings?

[ipsod]

https://github.com/wovo/psml/compare/master...ipsod:patch-1

[wovo]

personally, I never use diameter. that probably identifies me as not a mechanical person 🙂

let me think abut a solution. adding two named parameters is easy, and it would force the caller to be explicit: circle( d = 5 ) or circle( r = 2.5 ).

The problem would be when a cyclinder is specified by a vector instead of by individual parameters:

s = vector( 10, 20 ) c = cylinder( s )

So either

• remove this option
• live with it, 20 is the diameter or the radius, someone will disagree with no matter what
• idem, but add extra parameters to the vector constructor:

s = vector( 10, d = 20 ) s = vector( 10, r =20 )

I tend to the last option. Do you have a preference?

Wouter van Ooijen

0638150444 - HL15 4.060

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When dealing with mechanical parts, it's easier (possible) to measure diameter. You don't really see blueprints with radius specified - it's always diameter. So, why use radius in this program that's mostly used to make mechanical drawings?

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[ipsod]

I like the last option best. I like explicitness and {diameter}/2 is considerably harder to understand at a glance than d={diameter}. It could default to radius, like OpenSCAD does.

[wovo]

Circle etc. now have two parameters, radius and diameters, and you must provide one (but not both), adn it must be a named parameter.

For the cases where a vector is used to supply values it is still the radius. Maybe I'll find something for that, or I'll keep it that way, or I'll remove the option to supply a vector. I need more thinking time for that.

The examples still all use radius, I'll change that later.