Is there are a way to do a transition from one solid to another step by step? i mean if 1 solid is cube and 2 is sphere i want to get some transitional forms.

Unfortunately, I don't believe there's a way for MicroStation to animate a transformation from one element to another. What you can do is keyframe an element and script it, then move/scale/modify the element then keyframe it again and the animator will fill in the gaps between the two keyframes. You can read about that here: learn.bentley.com/.../ViewLearningPathWithMasterCourseExpanded;mcId=100131.

If you're referring to GenerativeComponents, I'm not sure if that has the capability. You might want to ask at the appropriate forum here: communities.bentley.com/.../360.

doesnt the  Loft tool do transition from one shape / solid 3d to another .. like with cylindrical ducting  to transition into truncated square based pyramid ( forgot the correct name for that shape)

then cant  you just take sections through copies?