XBR2D96D@DDATHD21.BITNET (Knobi der Rechnerschrat) (06/05/90)
Hallo, on Friday I tried to put our molecular modelling package MOLCAD onto an 4D/25 with the "turbo graphics" option installed. During that process I discovered the following behaviour: The molecular surfaces in MOLCAD are build from triangular meshes and lighted using the sgi lighting model. The surfaces can be either monocolor or multicolor. In the latter case each vertext has (worst case) a different material assigned to. On the G,GT,GTX and nod-TG PI's, this gives a soft scattering of the used colors. On the TG, the monocolored meshed look ok. The multicolored meshes on the other hand look flat, and you can see each triangle. It seems that only the last (first) color is used to display the triangle and that no lighting is done (may be, the normals are broken). Does this sound familiar? The machine is running 3.2.2 and is equipped with the RE2 chip set. Regards Martin Knoblauch TH-Darmstadt Physical Chemistry 1 Petersenstrasse 20 D-6100 Darmstadt, FRG BITNET: <XBR2D96D@DDATHD21>
bennett@sgi.com (Jim Bennett) (06/06/90)
Martin Knoblauch writes: > The molecular surfaces in MOLCAD are build from triangular meshes and > lighted using the sgi lighting model. The surfaces can be either monocolor > or multicolor. In the latter case each vertext has (worst case) a different > material assigned to. On the G,GT,GTX and nod-TG PI's, this gives a soft > scattering of the used colors. On the TG, the monocolored meshed look ok. > The multicolored meshes on the other hand look flat, and you can see each > triangle. It seems that only the last (first) color is used to display the > triangle and that no lighting is done (may be, the normals are broken). There is a bug in the TG in the 3.2 release which causes FLAT shading when tmeshes are used in combination with lmcolor. This is fixed in 3.3. In the mean time, you can draw the triangles as individual polygons to work around the problem. > Regards > Martin Knoblauch > > TH-Darmstadt > Physical Chemistry 1 > Petersenstrasse 20 > D-6100 Darmstadt, FRG Jim Bennett (bennett@esd.sgi.com)