I am working with a few engineers and they want me to convert the idw drawing file to a vsd "Visio" file for there redline process. They would like to be able to play with the line work in Visio. Is this possible?
No idea with Visio but my guess would be no they can't alter line work if you can get it to the correct format.
Have they looked at Design Review for doing the markups?
They do use Design Review but you are not able to edit the actual line work. You can only redline the drawing and then the drafters have to make the actual changes. They want to be able to make changes in Visio with the line work so then when the drafters are given the redlined drawings they will know exactly what the final product should look like instead of seeing a bunch of stuff crossed out and other things added. It sometimes can get a bit messy when they start doing total design changes off of existing drawings.
Perhaps one option may be to convert the IDW to an Autocad "DWG" file. The engineers can markup the DWG as well as add new lines as required without losing the integrity and traceability of the original drawing. Best though to do new line work on a new layer!
If the engineers do not have Autocad to do this they can use Draftsight instead (its free!).