As a general rule, we preferred native, parasolid, stp, iges in that order.
Native files we would translate into parasolid by way of TransMagic. We found better results by translating the files ourselves than having the submitter translate them before submittal (isn't that a word? Spell check doesn't think so).
Parasolid is a very robust format and seldom gave us any problems.
Iges was used only as a last resort, and even then it was often easier to recreate the file than use the translation, using only key surfaces from the iges file.
I hope that helps some.
"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]
For our (non parasolid based kernel) CAD system I would prefer STEP over Parasolid. There are many situations were a simple 2D transfer is all that's required. For that DXF is almost universally used.
As a general rule, I never send out native files, even if receiver has the same application. I've been burned one too many times by intrepid tinkerers who somehow tweaked my model and then delivered junk as a result.
Sure it's not perfect, and there are times when it's justified to use the native format, such as if it's more of a design collaboration than just 'make it as modeled', there's just more to think about in that situation.
Our way around that was strict control of submitted files. If questions ever arose as to unauthorized changes to the received file, the last saved by and date was easily verified by file history. Any modifications made by us would only be to copied or translated files.
"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]
