3D Autocad files to library object question

[Anonymous]

We received soem 3D autocad files that I've saved as archicad objects. They are working for what we need them for now. But it appears that every surface has a diagonal line on it in shaded view and in elevation. Is there a way I can get rid of that diagonal line? Here is part of the code:

*************
!!! Precaution against A == 0 or B == 0

BOXMAX = MAX(ABS(A), ABS(B), ABS(ZZYZX))
AA = A
IF ABS(AA) < 1E-5 THEN
AA = BOXMAX
ENDIF
BB = B
IF ABS(BB) < 1E-5 THEN
BB = BOXMAX
ENDIF
MODEL SURFACE
MUL AA/0.844416, BB/0.400050, ZZYZX/1.155700
XFORM TR3D_1_1, TR3D_1_2, TR3D_1_3, 0.0,
TR3D_2_1, TR3D_2_2, TR3D_2_3, 0.0,
TR3D_3_1, TR3D_3_2, TR3D_3_3, 0.0
RESOL 8
MATERIAL mat_1
LINE_TYPE "Solid Line"
PEN 20
!!LIN_ 0.71129369, 1.5397121e-005, 0.2159, 0.076293692, 1.5397121e-005, 0.2159
!!LIN_ 0.076293692, 1.5397121e-005, 0.2159, 0.076293692, 1.5397121e-005, 0.89535
!!LIN_ 0.076293692, 1.5397121e-005, 0.89535, 0.71129369, 1.5397121e-005, 0.89535
!!LIN_ 0.71129369, 1.5397121e-005, 0.89535, 0.71129369, 1.5397121e-005, 0.2159
PLANE 3,
0.71129369, 1.5397121e-005, 0.2159,
0.076293692, 1.5397121e-005, 0.89535,
0.71129369, 1.5397121e-005, 0.89535
PLANE 3,
0.71129369, 1.5397121e-005, 0.2159,
0.076293692, 1.5397121e-005, 0.2159,
0.076293692, 1.5397121e-005, 0.89535

**********************
The code is mainly made up of planes. ANy help would be great!!
Thanks,
Michele

[Anonymous]

The PLANE 3, ... statements are creating triangular surfaces. Two of them together make a rectangular (or at least quadrilateral) surface. The only way to fix this in the GDL code is to merge the nodes of the triangles into four sided figures. This could be quite tedious.

The better solution may be to see if you can get the files in a true 3D format such as 3DS where the conversion can produce true solids. I am assuming that you got DXF or DWG surface models.