I take it that you're going to have the vascular system as a kind-of stand alone.. I don't expect that you're going to go to the capilary level... One thing you can do, would be to use a low level model as a "form", lock the model to prevent accidentally adding it to what you want, then configure your veins and arteries to it... going from 2 to 3D will have to be somewhat intuitive, since you are the one who's going to have to determine how deep the vessels go... some of it will be common sense.. MOST arteries don't run close to the surface, and are little more than the "mains".. same with the veins... the larger it is, the deeper it usually is... though, with both, there ARE exceptions... as you model, you can turn visibility on and off in order to figure out "where" you are.... once donr, you should be able to just delete the model, and be left with just the vessels...... one thing.... if you're going to do whole-body, I'd start with the heart, and do the back half of the system first, then the front of the "body"... also, you'll want to start with the largest vessels FIRST... you can always "shrink" the smaller ones, as you go. BTW... this is what you get the "big bucks" for... converting a visualisation of 2D to a 3D. Lou.

"..... and that was when things got interestiing."