Does anyone know where I can get Technic beams that I can use in Photoshop or InDesign? I want to create a logo using Technic Beams. I have made the logo in LDD, but I want to see whether doing it directly in Photoshop or InDesign yields better results.

maybe a render or a screenshot of the part would work. I don't know where to get one of those that is high quality, though.

Lego bricks have precisely defined dimensions so it shouldn't be too difficult to draw them. Alternatively, some LDraw cads provide orthographic views of your build, which would probably work better than LDD for creating a logo.

You could also try bluerender for your LDD file