topic Re: MASS masking values: one for the Gurus in Libraries & objects

MASS masking values: one for the Gurus

David Collins — Sun, 20 Feb 2005 13:45:59 GMT

This weathervane rooster's body is made from two mirrored MASS objects, like a plastic model kit. The mask value is set to 21, all ridges smooth, so it looks okay in shaded 3d.

However, the contours show up in sections and elevations. Is there any way I can turn the contour lines off in hidden line views?

Re: MASS masking values: one for the Gurus

Anonymous — Sun, 20 Feb 2005 18:51:43 GMT

David,
To have the ridges be hidden you need to have the "s" values
of the surface points set to -1.
In this respect the MASS command is unlike the PRISM_ command.
Peter Devlin

Re: MASS masking values: one for the Gurus

David Collins — Mon, 21 Feb 2005 11:17:56 GMT

Thank you, peter! You da man!
This helped clean up my rooster wonderfully.

How on earth did you learn this? Was it just trial and error or is there some logic to this that has escaped me? The GDL manual only mentions the -1 status value as a kind of end marker, which is how I've always seen it used. I tried changing the status value to 1 or 0, but never imagined -1 would do anything but cook the rooster.

Re: MASS masking values: one for the Gurus

Anonymous — Mon, 21 Feb 2005 18:48:02 GMT

David,
Actually, I discovered this by accident.
The manual says the "s" values are "similar to the PRISM_ statement".
I modeled a pedestal sink with the Mesh tool with independent points
so that I would not have any ridge lines in the bowl and when I saved
the mesh as an object it was converted to the MASS command and,
to my surprise, all of the "s" values were -1.
So once again the manual is not complete.
Peter Devlin

Re: MASS masking values: one for the Gurus

Anonymous — Mon, 21 Feb 2005 21:33:22 GMT

Peter wrote:
So once again the manual is not complete.

Unfortunately, this is not new... all was said.
Why GDL is not a standard, despite the potential ?

Re: MASS masking values: one for the Gurus

David Collins — Tue, 22 Feb 2005 07:56:28 GMT

Peter,

I get it: the -1 value does make some sort of GDL sense. We're saying that each of these points on the MASS object is a separate entity. The code stops here. Incidently, I didn't know you could do insert just points into a mesh. That's going to be useful somewhere down the line.

The GDL manual is particularly unhelpful when it come to status codes. I have mostly learned about them by trial and error and looking at auto-scripted objects. I understand the logic behind the numbers and have even come to a grudging appreciation of the binary system, but every time I see "s = j1 + 2*j2 + 4*j3 + 8*j4 + 16*j5 + 32*j6 + 64*j7 [+ a_code] where j1, j2, j3, j4, j5, j6, j7 can be 0 or 1..." I just want to bang my head on the table.

Re: MASS masking values: one for the Gurus

Anonymous — Tue, 22 Feb 2005 19:24:14 GMT

David,
To insert independent points in a mesh, set the geometry method
to polygon and double click in the mesh where you want a point
created, and then assign it an elevation.
As to the binary system, I agree, it is tedious but necessary.
Peter Devlin