I'm using several buildings in my current scene, which were created as a .max asset.
However, when i edit this max file, some instances of the asset seem to have there rotation and/or scale transform values altered (in increments of 100 (scale) or 90 degrees (rotation). Any pointers as to what might lead to this behaviour?
Also, is there a way to align assets (buildings) to the terrain height? I've only found an align to view function.
From my experience, in 3ds Max Z axis is up, and in Unity, Y axis is up. And I don't bring in the max file to Unity. So what I do is to export each building as a separate object (each building in its own max file, thereby eliminating different axis problem), and export as .fbx and there's a checkbox where you have to select "convert to Y axis" (something like that). Then import the .fbx object into Unity.
In 3ds max, select your object. Then goto the Hierarchy Panel (the tab just before the wheel on the side rollout) under the "Adjust Pivot", Select "Affect Pivot Only".
Now use the rotate gizmo to move the Y axis (the red arrow in 3ds Max) facing upward. For More precise control use the "Absolute/Offset Mode Transform Type-In" found on the bottom status bar. Once the Pivot is correct for Unity (Y Axis for the pivot facing upward)
be sure to turn off the "Affect pivot Only" button.
If your .max file contains multiple objects, each with a different angle for their axes, then Unity will give them all a uniform set of axes to follow. For example, if you rotated a building but rotated its world axis within 3DS as well as the building itself, this would be altered by Unity. Make sure you leave the axis tool alone in the 3D app and only use the object rotate tool.