No more of an issue than the people who manufacture the pen and ink you use to draw the characters. Byrce is a tool used to create 3d art, as long as you don't claim you created Bryce, then they can't claim any rights to what you create. Carried to it's logical obserdity, then Intel and Microsoft could claim rights to everything done on any of their platforms. If I use 3DMax to create a model, I can still sell that model. The same with one created in Bryce. Bryce is the tool, the intellectual property comes from you.