So I have this parking lot infront of my building. The striping on the asphalt are white rectangles 1/2inch above. I need them to not cast any shadows from the GI, otherwise they look like they are floating above. In the VRay System roll-up - Object Properties - I turned off 'Generate GI", left on “Receive GI”, and turned off “No GI on other mattes”. I also turned off shadows in the Max properties.
Any suggestions?
Thanks
Joe
why not just use a texture map for them
Oh, yeah, this is part of a huge parking lot with tons of stripes in lots of different orientations. Thus, it would be a huge map. Any renderings where there are stripes near by, they might be pixilated. As vectors, they are nice any crispy!
If you turn off “Visible to reflection/refraction” in the object properties for the white stripe it will actually not cast GI shadows.. of course it won’t show up in your reflections, but if you don’t have that in your scene this “trick” should work.. well.. not really a trick, looks more like a bug to me 
/Thomas
just a surgestion… but why dont you use splines and give them a rendering thickness…hey well thats what i would do any how…
…never sleep…
re
The stripes are planes and moved just slightly above the conc plane, just enough to where the stripes barely clear the plane. After that all I did was go to the stripes’ properties and uncheck cast shadows.
Here’s another thought. Make all the parking stripes splines, attaching them together to make one spline collection. Then do a ShapeMerge (Merge) with the parking plane. Now if convert the object to an Editable Poly sub-object element the stripes should be selected. Set their Material ID to 2. Now apply a Multi/Sub-Object material to the parking lot with mat. 1 being the concrete and mat. 2 being the stripes.
So what does this get you. No fussing with shadows and if you have a texture map for the concrete you can use it in the stripe paint, to a lesser degree, to give it a continuous feel.
Not worth much just a thought.
JoeD
Wow! Thank you guys for all your help. Great advice!
If you are planning to save your irradience map, you could simply unhide them during the calculation. then unhide them afterwards when rendering..
-Tom
This is the way I always do my parking lots. Simply a box extruded 1/16" and set directly on the pavement surface. You’ll probably never notice shadows. You might want to add a bit of transparency so you pick up a bit of the texture below.
I know this method adds to the face count, but I generally only do one view, and only around 15 spaces might show in my view.
Alternatively, if face count is an issue, you could position all of your rectangles, move them up a fraction above the pavement in the Z axis, extrude them some rediculous amount in the negative direction so they extrude down below the pavement like 30 feet, union them, change to a side view, explode the stripes, and delete the side and bottom faces. This will leave you with only the top face, with the correct normal (facing up).