I want to reach 3D artists who do real-time architectural modeling.
What web sites would best target these people?
I'm doing this kind of things..if you interested i can send you few works i did in past (some of them implemented with Blitz3D)...whats the deal?
Are you talking forum spam or banner adverts?
if you don't mind spending a bit of money - how about a print ad in 3DWorld magazine?
Coming from an Architectural background and having a strong 3d hobby (using XSI), I would say you're best choices for an Arch viz advertising campaign are:
www.cgarchitect.com
www.cgtalk.com
I noticed on your 3d World studio, you mention importing:
.x, .obj, .md3, or .gls meshes.
I highly recommend adding additional formats such as 3dmax, Autodesks Viz, any Autodesk product as Architects or arch viz projects many times are born from these products. Microstation, Form Z, Rhino, Brazil imports would also be useful to firms/architecture students. I've used all of these products and they are standard for arch viz.