Questions for nxt render for autocad

Good day everyone,
Can anyone here help me with these issues i keep having with nxt render for autocad ?
1. How do you bring in textured models into autocad ( 3ds and obj) without losing their textures or having to re-assign them.
2. How do you move these objects from place to place without experiencing viewport refresh sluggishness in the autocad viewport ?
3. How do you add dirt to fabric textures for rendering.
4. How do you avoid repeat patterns in textures for rendering ?