Rendering - Viewport Background Image offset
There is a potential issue for users when working with Background Images loaded in the Viewport in 3ds Max or 3ds Max Design. The background image may appear offset from how it appears in the Viewport when rendered if the Mapping method is not set to Screen.
The issue may be apparent when using a setup similar to the following:-
1. An environment map has been loaded for render. This can be done from the main menu - Rendering>Environment(8)>Common parameters rollout>Environment Map as shown below:-
2. You have created an instance of the Map in the Material editor for edit. This can be done either by Alt+dragging the material from the Environment Map rollout(8) to main view in Slate Material Editor(M) or by Alt+dragging the material to an empty Material slot in Compact Material Editor:-
3. The map has also been loaded as Viewport Background for display. This can be done from the main menu – Views>Viewport background(Alt+B) – if Environment Background Map already loaded as in step 1, you can select Use Environment Background option as shown below:-
4. With the map loaded as Environment Map for Render and Viewport background for realtime display in Viewport-The Slate Material Editor(M) or Compact Material Editor has been opened.
5. In the Material Editor>Coordinates rollout, the Mapping method has been set to Cylindrical, Spherical or Shrink-wrap environment. The U/V offset and tiling values have been modified to scale and tile the background image:-
Result: When rendered, the Background image will appear offset from what is displayed in the Viewport Background. This can be seen in the screenshot below, the render on the left appears cropped, the scaling is different and the position is off from what is displayed in the Perspective Viewport on right:-
This issue is caused by using Cylindrical Environment mapping for the Material (see step 5 above) The Viewport background image will not match the Environment map used for render unless the Coordinate mapping method is set to Screen. To resolve the issue, follow the steps below:-
1. Open Slate Material Editor(M)
2. Select Material map used as Background Environment Map and Viewport Background.
3. With Material Map selected, go to map Coordinates rollout and ensure that method is set to Environ and Mapping set to Screen:-
The background image should then render correctly with the image placement and scaling matching settings in material Editor and Viewport:-