Ground Strands changes the position of the strands
Guides or hairs created from Spline Curves will change its position when grounded using Ground Strands modifier.
Problem
During grounding the hair object is parented and aligned with the surface object such that their object transforms are the same. This is important and needed for operations down the modifier stack. But the object centers of hair and surface mesh are in different places, so the hair mesh will be moved first before being grounded.
Solution
This workaround assumes the Spline Curves are already converted to Ornatrix guides.
- Select Spline Curves object, parent it under your Scalp object
- Change Reference Coordinate System dropdown to Parent (in main toolbar)
- Reset X, Y, and Z coordinates to 0 (in Max's transform type-in). This will move the splines to be aligned with the base surface.
- Go to the Editable Spline base object of the hair. Select Spline mode, and select all splines.
- Move the splines back to their desired position, this time in object space
- Go back to Ox Ground Strands and ground the strands. This time it will work correctly.
Note that Reset X-Form is not needed at all in this case. It is only needed when scaling is applied to hair and/or the base mesh, which is not the case here. X-Form is not needed at all in this case. It is only needed when scaling is applied to hair and/or the base mesh, which is not the case here.
Solution 2
As an alternative you can manually align the pivots of both objects. This workaround assumes that you have not converted the Spline Curves to Ornatrix guides yet.
- Select the Spline Curves and go to Hierarchy tab and turn on Affect Pivot Only.
- Activate the Align Selection tool and set Current Object and Target Object to Pivot Point, then click OK. This will align the pivot of the spline curves to the pivot of the scalp.
- Open the Transform Tools from the Edit menu and click the R to Reset X-Form.
- Add hair to the spline curves and ground it as usual using Ground Strands modifier.