Typically we get emails from clients asking what format of file should they be sending to us. For architectural work it is rather straight forward and we can tell them AutoCad DWG/DXF for 2D and if they have 3D work we can use that as well. But more and more clients have Revit or SketchUp files that if done correctly can save us time in the modeling process, if done poorly we may as well model from scratch. But the biggest challenge is for Product Illustration where the Client has and engineering department modeling with a "Solid Surface" modeling software package intended for CAD/CAM manufacturing or in the least "Mechanical Engineering". Here things can get a bit difficult........

The email response typically goes something like this:

Dear Client,

I don't know what software you use and it's exporting capabilities. Skip to bottom for short answer.

On top of that programs like Inventor and SolidWorks treat things like holes/perforations differently and more efficiently than 3D modeling/rendering sofware so if you have perforated stair treads me may end up getting a version from you that doesn't have the perforations in the actual geometry and we can make a texture that has transparency channels at the perforation locations and at render time for all intents and purposes the holes are there and you can see through them etc.. I mention this because we recently got a big metal structure from a client and it was a nightmare to work with, turned out there were like 80 million perforations in the structure and our software had to translate and interpret them all, the file was gigabytes in size and it was a nightmare until we figured it out and went with the approach I mention.

Short Answer:
With all that said your software probably exports out to at least one of these and they are acceptable usually and we do have the industry standard in conversion software so we can usually handle just about anything, but the following import directly into 3DS Max (software we typically use) and would be the easiest solution:

STEP (*.STP)
Solid Works (*.SLDPRT, *.SLDASM.)
Autodesk Inventor (*.IPT, *.IAM)
StereoLitho (*.STL)
ACIS SAT (*.SAT)
ProE (*.PRT, *.NEU, *.G, *ASM)
Catia V4 (*.MODEL, *.MDL, *.SESSION, *.EXP, *.DLV, *.DLV3, *.DLV4)
IGES (*.IGE, *IGS, *.IGES)

Some standard formats for 3D files that aren't 3D Solids, but can be used as well, especially for vehicle and architectural models:
Autocad (*.DWG, *.DXF)
Autodesk 3ds Max (*.MAX)
Autodesk Maya (*.MB)
Autodesk Design Web Format (*.DWF)
Kaydara (*.FBX)
COLLADA - COLLAborative Design Activity (*.DAE)
Wavefront (*.OBJ)
Revit (*.RVT)
SketchUP (*.SKP)  
Maxon Cinema 4D (*.C4D)
………

We can work with you and chances are whatever you have we can convert, but some formats play better with others.