I suppose a big concern for many is how explicit the image is. I have very little interest in bondage (I do dig the fashion though) and no interest in gore or depictions of extreme suffering. On the other hand, I do love the works of artists like Masamune Shirow, and Paolo Eleuteri Serpieri. Somewhere between cheesecake/fan service and modern XXX might be my happy medium. Beyond that and I get an icky feeling.

But it's not specifically the moral aspect that has kept me away from seriously attempting adult imagery/animation. Physical contact, especially sexual contact, really pushes the limits of the tools I have at my disposal. Joint bending, body mass inertia, believable hands-on contact... It's only a minority of CG artists who have the skill or patience to depict those things correctly.