CAD models are commonly drafted in worldscale (1:1). When importing such CAD models for documentation or presentation graphics with Corel DESIGNER, you will usually not use the real world scale but rather a 1:100 scaled drawing (for an architectural plan) or a 1:10 (manufacturing detail) or any other downscaled representation of the original CAD drawing.This is especially needed when importing very large CAD models (i.e. an environmental map) that do not fit on any page size you want to set up for your desired layout. Such CAD models so far have been scaled (in the background) to fit the maximum application desktop size when being imported.
Note: Make sure you have the most recent version installed! The enhanced .DWG import options are available in Corel DESIGNER X5 with Hot Fix 2 applied only.You can download the available Service Packs and updates from here.
With the additional information about the original size of the CAD model (provided in the Import dialog) you now have great control over the imported drawing and can make sure your drawing has the right scale before you even place it into the illustration.
Additional tip for 3D model handling: You can select from the orthographic and isometric projected preset views in the "3D Projection" dropdown list when importing. If you need additional options (other views to the original 3D CAD model) you should take a look at CorelCAD with its "Export to Corel DESIGNER" tool. With CorelCAD you can export any custom model space view of a 3D CAD model to *.DES (or *.CDR) directly.