When multiple semi-transparent objects are present in a VAPOR scene, these objects may not display properly in the sense that objects in the back may appear to be in front or vice versa. VAPOR does provide limited sorting of semi-transparent objects, so that two objects that are completely disjoint and ordered in distance to the camera (say two parallel planes orthogonal to the view direction) will usually be displayed properly. However this separation of objects is not always possible; for example when multiple semi-transparent isosurfaces are shown in the same scene.
For improved transparency rendering, VAPOR supports a technique known as "Depth Peeling". In the VAPOR User Preferences panel is a checkbox "Enable Improved Transparency Rendering". After this box is checked (or unchecked) you must save the preferences to a file and restart VAPOR GUI in order for this setting to take effect. When enabled, most semitransparent objects in the 3D scene, with the exception of DVR volumes, will display with the correct transparency ordering. However users should note the following:
