Download TranspRef 2.0 - unlimited transparent positionable reference images.  


This plugin fills in another gap in the Blender modelling experience. It provides a means of setting up an unlimited amount of "background images", or to be more precise "reference images". noThese planes can be positioned/scaled/deformed to your liking and will seemingly appear behind your transparently rendered geometry. In fact the reference planes are transparent themselves and drawn on top of the geometry. This means it is possible to use the planes for both sides of your geometry (front/back, right/left, top/bottom), whatever way you look at them, they will always be drawn transparently on top of the geometry.

Go to User Preferences->Addons and enable the TranspRef addon in the 3D View section. A TransRef pulldown will appear in the N panel (pull + icon on right of 3D view). It will be empty until you select a standard Mesh->Plane with four vertices.  Click the file browser icon in the N panel->Transpref section and load up an image, the image will be projected over the scene contents, carefully filling the space bounded by the selected plane, which you can afterwards translate, rotate, scale and deform(editmode) to your wishes. When you select an image, also a Transparency slider will appear, put it somewhere low so you can see your geometry behind the reference planes.
Works well in perspective mode now too.

NOTE: the reference planes shouldnt occlude object selection, thats why you can only select them by clicking the plane edges.

NOTE: you can create as many reference planes as needed. Reselecting a plane later, enables you to access image path and transparency values.

HINT: you can use the reference planes from both sides. I recommend to model in orthogonal mode (which is a good idea anyhow) if you want this to work correctly.

BEWARE: reference state will be saved along with your blend file