you should be able to bring the .dwg file straight into showcase
its not a perfect conversion if i remember correctly it brings the model in black but its a good starting point
It's very dificult insert big plant models in showcase...In this moment showcase is not usefull for plant design, in my opinion.
3D Studio Max Design is designed to handle large models such as one exported from Plant 3D. Showcase seems to work fine for individual models or small skid based designs, but for large projects 3D Studio is the way to go.
What I found for importing from Plant 3D into Showcase is exploding all the entities, and works a little more better.
Showcase does not currently support AP3D Object enablers. You can import an AP3D model into Showcase but it requires exporttoautocad which converts plant objects into native AutoCAD entities.
It worked with decent performance when I tried it (attached) on the relatively small 2012 sample project.
Seems nothing has changed in 2013, same issue where Plant3D objects don't make it into Showcase. I loaded the sample project, Master.dwg, then tried the Xref 2-P-001 by itself, no pipes nor racks at all either way. So, I tried the workflow to 3DS which did better, but lost all the pipe fittings.
Kinda messes up the whole integrated workflow thingy.