Hi guys, I also struggle with this. I am very new to Archicad so apologies if I'm missing something obvious.
Everything in my 3d window looks grey. I am trying to make a colorbond shed. When I go to options / element attributes / materials I change the surface colour to anything (like bright green) nothing happens in the 3D window. I understand from the posts above that it won't change the 3D it will only change what gets output when you do a photorender. So I do a photorender ane the whole thing still looks grey.
When I choose other items for the walls and roof from the model settings like Brick, the brick colours show up fine in both views showing the texture and the color but the chanegs to the material colour that I make dont' seem to work. I have tried the internal rendering engine and the lightworks rendering engine (I don't really understand what they mean). I have tried all rendering engines in fact both on the material settings and the photo render settings. I select every option that I think could have an impact on the quality of the final render but no good.
I also in desperation found the corrogated iron texture in the library, coped it, edited it in photoshop to give it a new colour, re-loaded the library then selected the new texture in the material window. this didn't change the appearance either in the 3D window or in the photorender immediately but then at some point (im not exactly sure when) seemed to change everything on the page (all walls, roofs etc) to the new material. Which is not what I wanted but I seem to be getting somewhere. If there is something obvious that I am doing that anyone can help with please let me know otherwise I'll push on anyway and if I figure it out I'll post back with where I got to with it!