Getting an Autocad file into Maya without special conversion software isn’t impossible, at least for a simple model:

Step 1. Go to the Plug-In Manager.

Step 2. Check that dwgTranslator and objExport are turned on.

Step 3. Switch Maya into Modeling mode.

Step 4. Choose the Import option box.

Step 5. Set the File Type to DWG_DXF, and set the Scale Factor to 0.001 (otherwise, Maya will blow your DWG up to an enormous size). Click Import when you’re done.

Step 6. Import the file.

Step 7. Call up the Outliner window.

Step 8. DWGs will sometimes arrive in many pieces. Use the Outliner to select all these pieces, and then use the Group command to lump the parts together. (If your file’s parts are already grouped together, you can skip this step.)

Step 9. With your new group of parts selected, choose Combine from the Polygons menu. This will turn the separate parts into a single object.

Step 10. Make sure your new combined polygon object is selected, or else the next step won’t work.

Step 11. Choose Delete By Type/History from the Edit menu. This will break the links between your new object and the old group of imported parts.

Step 12. Select your old group of parts and delete them. (If your new object suddenly disappears instead, you didn’t delete its History properly.)

Step 13. The next three steps set up your new object so it works properly in Maya. First, choose Center Pivot from the Modify menu.

Step 14. Next, choose Texture/Automatic Mapping from the Edit Polygons menu. (You can use any of the commands in the Texture menu to prepare the model for texturing, but I think this is the easiest to start with.)

Step 15. Finally, as an optional step, you can choose Normals/Reverse from the Edit Polygons menu if the model appears to be shading strangely.

Step 16. That done, you’re ready to texture the model. Switch Maya to Rendering mode.

Step 17. Choose Assign New Material from the Lighting/Shading menu. Here, I chose Lambert.

Step 18. Add a texture and check your results–you may need to do some more tweaking before you’re satisfied, but at this point the model should behave normally in Maya.

If you’re still not happy, you might want to try changing your original file’s export settings in Autocad. (I’d recommend avoiding settings that create unnecessary triangles whenever possible.)