CAD and Collada

I do a research for a 3d CAD open format.
Can I use COLLADA for this reason?
I will create my own OpenGL CAD renderer, so I don’t care about implementations.
The question is only about specification. Can I use COLLADA for CAD purposes?

SVG is good enough for me but it is only 2D, so I must reject it.

Yes, COLLADA 1.5 specification is adding elements specific for using in CAD.
Specifically the B-rep and Kinematics sections.
GEt the 1.5 specification here:
See this thread for sample and access to converters … 5&start=15

COLLADA 1.5 is the core component of automationML, , an interchange XML standard for the automation (robot) industry, used in car manufacturing for instance. the Automation ML group has some software (.NET/C#) that may be useful to you, you may want to contact them.