Depending on which industry you are in, the nominal pipe diameters are either given for the inside diameter or the outside diameter, and then the thickness.
Frankly, I think it’s mostly the later, which Rhino doesn’t seem to account for.
If your input for the “Pipe” command is a single curve, entering a negative number for the thickness will produce a logical result : the OD is the one that was entered and the thickness is “inwards”. Great.
But if you select multiple curves, it will either take the absolute value of your thickness and therefore create an inner diameter + “outward” thickness, or… do absolutely nothing.
Thankfully, I can use Grasshopper to get things done, but really, it’s time to fix this “Pipe” command !
Well, this is not exactly what I asked for.
Using a negative value for the thickness makes sense to me for decribing the pipe in a “OD+thickness” context. The problem is that it works when the input is a single curve, but not when there are multiple curves : this is a bug.
The title of that ticket is possibly misleading. The description of the current bug is in the “Observations” part, where it says “Only positive values are allowed, […]”.
At any rate, I’ve added a clarification.
I’m sure someone will come back in a few years asking for a setting so that they don’t have to think about using a negative value…
-wim
It’s interesting that the negative input works for single curves.
I don’t want to mess with @osuire request but let’s say the specs of the pipe would be saved as user attribute. A pipe would need at least two attributes (ID, OD, t)… Just a thought… From that point of view it would probably make sense to have an ID / OD input option and ignore the prefix.
You are right : I updated the title.
To be honnest, I don’t care if you correct the bug with the negative thickness, or if there is an option to specify if the specified diameter is OD or ID.
Please, just allow users to generate multiple pipes with the geometry they want in a way that makes sense.
This is so basic…
Similarly, in the “ExtrudeCrv” and “ExtrudeSrf” commands, the fact that the height you enter is doubled if the option “Both Sides” is set to “Yes” makes no practical sense.
No one thinks of an extruded part as having “twice it’s half-height”.
Except maybe in Subsea oil and gass, I don’t know…
I bet that this silly logic has been the cause of many fabrication mistakes, as absolutely no CAD system I know does this.
