AC mesh vs gdl mass

[jclewis]

The mass tool is suppose to be "The equivalent of the shape generated by the Mesh tool in ArchiCAD", but this does not seem to be the case in certain circumstances.

When using the additional status codes to create an arc for a segment of the mass and when the z-values of the two endpoints of that segment are different, the resulting object is not the same as a similarly created mesh (see the illustration).

The mesh creates a smooth vertical transition from the first height to the second height, with each node in the curve having the same vertical rise as all of the other nodes. This is the correct behavior, or at least the behavior that I want.

The mass object, however, does not do this: it assign the entire vertical rise to the very first node and the remaining nodes are all flat (that is, equal to the ending z-value). This certainly is not the same behavior as the mesh and not what I need. (The number of nodes in the mass segment--which depends on the specified resol--is less than the number of node in a mesh, but I haven't found any different behavior as resol is varied.)

Is this really the way this tool should work? Any suggestions?

Thanks

[Anonymous]

May I understand you used additional status codes for arcs (3000, 4000, etc.), into the MASS tool?
They are not supposed to work with MASS.
The weird thing, is that not only 3D model shows, but it doesn't display any checkscript alert.

Scripting from scratch, you have to define yourself nodes for rounded contour,
and assign each of them an accurate z coordinate with some trigo. Use a status code 15+64 for smoothness.

As start example, save your mesh as an object, to see how GDL handles these contour points.
After that try to reduce script with a loop for rounded contour nodes.

[jclewis]

Thats odd. Page 87 of AC 12 GDL Reference Guide:

See “Additional Status Codes” on page141 for details.

And they do work--quite well horizontally, very poorly vertically.

[Anonymous]

jclewis wrote:
Thats odd. Page 87 of AC 12 GDL Reference Guide:

See “Additional Status Codes” on page141 for details.

And they do work--quite well horizontally, very poorly vertically.

James,

This is another example of how cryptic is the Reference Guide.
Some pages before, you can read with which tools these 2D additional status code are intended to work. MASS is not include.
GS explanation mixes various 3D status codes with 2D (x,y) additional status code. This is IMHO an error.
There is not any z coordinate for 2D additional status code. The dangerous thing is that, despite this, it can work (wrong) in this particular situation.

GS, Please. The bad script should display a checkscript alert.
Not only it doesn't, but 3D model shows. Weird.
IMO, this is risky. Users may think this is correct scripting.

Greetings to all.

EPS = 0.0001
resol 24

!!! ----- correction -----
! for k = 0 to 90+EPS step 360/24
! put cos(360-k), sin(360-k), 0.20*(1-k/90), 15+64
! next k

!!! ----- bad scripting -----
put 0.00, 0.00 , 0.10, 900
put 0.00, -90 , 0.00, 4000+15+64

mass matTop, matBot, matSide,
5+nsp/4, 1, 1+4+16+128, -0.5,

1.00, 1.00 , 0.20, 15, ! contour
1.00, 0.00 , 0.20, 15+64,
get(nsp),
-1.00, -1.00 , 0.00, 15,
-1.00, 1.00 , 0.20, 15,
1.00, 1.00 , 0.20, -1,

0.00, 0.00 , 0.15, -1 ! centre point

[jclewis]

Olivier

OK, that makes some sense.

Without the z coordinate, the addition status code must assign the beginning or ending z value to all nodes, hence the strange behavior.

I agree, the Reference Guides are weak.

Thanks for your help.