If the current 3D structure consists of grains or fibers that intersect (or overlap) with each other, you can use the Remove Object Overlap command to modify the current 3D structure such that the overlap between the individual objects is minimized.

The options of Remove Object Overlap are similar to the choices available under the Generation and Overlap Mode panel of FiberGeo for fibrous structures (FiberGeo Create Options dialog) and GrainGeo for structures with granular objects (GrainGeo Create Grains Options dialog).

Removing overlap in dense structures is a complex process that requires some time, depending on the imposed restrictions. In the Stopping Criterion panel, select the maximal number of Iterations for the algorithm to finish, how many iterations should be allowed when the solid volume percentage does not change anymore (Iterations SVP Unchanged) and the maximal overlap permitted for the process to finish (Overlap SVP / (%)).

The overlap of objects is removed by shifting, rotating, and/or deforming the objects. Choose which processes should be carried out and the way in which they should be done.

After checking Allow Object Shifts, choose the allowed Number of Shifts and the magnitude of the shifts (Shift Distance) in voxels.

In a similar way, select to Allow Object Rotations and the Number of Rotations, or to Allow Fiber Deformations, and then the Maximal Bending Angle for the deformations.

Choose the Distance Mode between Touching, Defined Overlap, Defined Isolation and Avoid Contact to set the separation that should be achieved between objects. For Defined Overlap, set the Distance that objects are still allowed to overlap. For Defined Isolation, set the minimal Distance required between two objects.

Overlap and distances between objects are determined based on the voxel representation of the GAD objects, not between the analytic objects themselves. Therefore, the outcome is resolution dependent, and objects not overlapping in a certain resolution might slightly overlap in a different voxel grid.

Various realizations of the overlap removal with the specified options can be obtained by changing the Random Seed. If all other settings are equal, overlap removal operations with the same Random Seed value produce exactly the same structure.

For example, overlap of fibers can be removed from a fibrous structure with SVP of 35%, using the default values in the Remove Object Overlap dialog. The gray areas correspond to the overlap between the red fibers.

Observe how the shape and the position of the fibers have been modified to avoid the overlap.

Depending on the stopping criterion reached, it is possible that the remaining structure still contains some overlap. The current overlap settings decide which material ID the overlap material gets. You may use the Edit Domain command to redefine the overlap behavior, e.g. to mark overlapping parts with a different material ID.