You don't "need" an accelerator. I think it would "work" on 68000. Are you sure Real 3D requires an FPU. I used the first version on my A500, up to 1.4 I think, maybe I had an 030 with FPU, don't remember. Then version 2.0, a total reprogrammed package.. and up to I think version 3.5. I used Real 3D.
I think Real 3D was to hard and time consuming to use in reality, great features in specs, like particle systems, kinematics, spline modelling, multiple cameras, advanced lightening, etc.
I think Lightwave would have been a better choice, and made my life more easy kind off.