Troubleshoot rendered image doesn’t match interactive window display

User Guide > Rendering and Render Setup > Rendering > Visualize and render images > Visualize scenes and render images > Troubleshooting Rendering >

In rare cases, a rendered image may not match what is displayed in the interactive window. This may be caused by different Dependency Graph solutions if nodes are evaluated in a different order.

The most common occurrences are: renders that are divided among multiple machines produce inconsistent results; an arbitrary frame within an animation range is rendered alone; or rendering with motion blur produces different results than rendering without motion blur.

Scene elements which may produce undesirable render matching include:

Any dependency graph cycle.
Animated nodeState on any node.
Animated transform limits.
The multi-chain IK solver.
Expressions that modify values based on a previous value. For example: tx = tx + 1.
Expressions that conditionally set values. For example: if (ty > 5) tx = ty.
Expressions that execute commands (or create or delete Maya nodes). For example: sphere.
Particle/softbody solutions (because of timestep changes).
Geometry Constraint nodes (because they go to the point on the target geometry that is closest to the current point).
Any constraint where the sum of the target weights is zero.
Aim, tangent, or normal constraint or lookAt nodes with the worldUpType attribute set to None.
Aim, tangent, or normal constraint or lookAt nodes with the upVector co-linear with the aimVector.
IK with an animated solverEnable value.

Workaround

The renderer can invoke a MEL procedure just before you render a frame. (You specify this script in the Render Settings > Render Options > PreRender Mel text field.) You can use this procedure to force evaluation at the intervening skipped frames.

To use a MEL script

Put the MEL script (named preFrameProc.mel) in your Maya scripts directory.
Under Render Settings > Render Options, type preFrameProc in the PreRender Mel field.
If motion blur is on, you may need to bake the animation.