I can see from various examples that FUD & FXD are translucent, but it would be very useful to have more data. Does anyone know the optical properties of the material? I'm thinking of things like refraction index, absorption coefficient, scattering and gloss. I realise this is a lot to ask, but it would really help with the design process.
The MSDS linked from its materials page tells us it is 3Dsystems' Visijet SR200 , but 3DSystems appear to provide only mechanical properties of the cured material (apparently they consider it a structural material, while they sell other acrylics for optical applications). Perhaps your best bet is to buy either a shapeways materials sample kit, or a FUD/FXD part from the shop section that is cheap and/or similar to what you have in mind. (stop4stuff's kraken in crystal would be one possibility) BTW a cursory search turned up this link to a Malaysian university report on the burnout properties of this material when used as a pattern in investment casting. (Absolutely not what you were asking, but that question comes up semi-regularly here as well, so may help somebody who uses the forum search)
Hey Mkroeker- i can't tell you about the specific scientific properties of FUD, but I can tell you that when you first look at this material it is quite frosted, and only looks optical on certain areas (this is due to the support material and cleaning solvent used on the products). The higher detail you go, the more optical the product will be (FD: Least transparent, FUD: More transparency, FXD: Best transparency ). There are some post production techniques to polish off the models to make them more transparent - you can also add a clear coat to add to it. I recommend searching through the post-production techniques for "FUD" material... you'll gain a lot of information that way. Hope this helps!
Maybe that's different between NL and US factory, dependent on print orientation, or cleaning procedures that change over time - the only FUD model in my collection is Theo Jansen's "strandbeest larva", and it was quite transparent out of the box, only acquiring a few yellow spots later, presumably from traces of aging support wax. (And I think I remember from previous discussions in post production techniques and elsewhere that stop4stuff wrote that he needed to do little if any post-processing on the kraken - the main worry with this model being if your technicians would always honor the "trapped support wax for aesthetic reasons" exception to the escape hole size rules.)