Enable background image in 3D View Space when not aligned to an axis or camera?

What code in the blender source would I need to modify in order to have the option to make a background image visible in the 3D view-port even when it is not aligned to the X, Y, or Z axis in the orthographic mode?

I realize that I can get this same “effect” with no mod’s by using the camera view but I find the camera movements to be less intuitive. Also, the view-frustum aspect-ratio matching setup is too tiring.

This image represents a method of lining up the mesh that is being edited with a background photo of the subject in order to see that it matches up. In this case it is dependent on the window manager’s ability to change the opacity of the window with ALT-Scrollwheel. This allows the inactive window containing the subject behind the blender window to bleed through.

This particular shot of the subject car was taken with a 1000mm telephoto lens (or thereabouts). In order to overcome the hardcoded, readonly, 250mm lens limit in the SpaceView3D.lens property, I rebuilt blender with the following change to rna_space.c:

   prop= RNA_def_property(srna, "lens", PROP_FLOAT, PROP_NONE);
   RNA_def_property_float_sdna(prop, NULL, "lens");
   RNA_def_property_ui_text(prop, "Lens", "Lens angle (mm) in perspective view");
   RNA_def_property_range(prop, 1.0f, 1000.0f); // right here change 250 to 1000
   RNA_def_property_update(prop, NC_SPACE|ND_SPACE_VIEW3D, NULL);

About the time I accidentally bumped the “turntable” I decided that this is a silly idea. I’m putting my blender back to stock. I’ll just learn to make better use of the camera.

you could use empty objects image display option too. - since these can be moved about as you like.