How can I zoom in and out in the Prostream BIM Viewer?

You can zoom in and out using the zoom function in Prostreams BIM viewer.

Select the zoom icon (arrow) and select in the model the part you want to zoom in or out. Double-click and that's it! 

You can also use the arrow cursor to click and drag the image to the desired scale. Dragging down increases the scale of the image; dragging up decreases the scale. Release the mouse button when the image has the desired magnification. The zoom command remains active until you select another command.