Reset Block Transformation Matrix

[silvano]

@dale I am trying to reset the transform of a block instance - the matrix highlighted in the screenshot below.

I tried a mix of the following.

Rest Block Transformations?

Hi! Thank you, but I am afraid the script isn’t doing what I need, I think this one only resets scale… I runs okay, but I can see the block has not been reset by looking at the gumball. Then I check the Base Point of the Block, and indeed it is still located differently from a newly inserted block.

and

Reset (or change) block instances transformations (scale, rotation)

Hello, my question is about block instances. When you create a new instance of a block, you can change its rotation and scale, and this is great. But what if you want to select a block instance and reset its rotation or/and scale? For example, I create this block. I create some block instances with different rotations (Every instance has a specific transformation matrix) Now… There is a way to “reset” selected block instances? Or a way to set all these instances with a rotation o…

# Resets a block instance by modifying its transformation to be
# translation only. Thus, only position (not rotation or scale)
# are retained.
import rhinoscriptsyntax as rs


def main():	
    blocks = rs.GetObjects("Select block instances to reset",
                           filter=rs.filter.instance, preselect=True)
    if not blocks:
        return
    rs.EnableRedraw(False)
    for str_block in blocks:
        xform = rs.BlockInstanceXform(str_block)
        xform_inverse = xform.TryGetInverse()[1]
        rs.TransformObject(id, xform_inverse)
    rs.EnableRedraw(True)

if __name__ == '__main__':
    main()

It seems like rs.Transform() excludes block transforms and rs.BlockInstanceXform() does not have the second argument anymore, that allows to set the matrix of the block. Is there any other way to change the block transformation matrix?

Thanks for your help.

[dale (Dale Fugier)]

Hi @silvano,

How about this?

# Resets a block instance by modifying its transformation to be
# translation only. Thus, only position (not rotation or scale)
# is retained.

import Rhino
import scriptcontext as sc

def ResetBlock():
    filter = Rhino.DocObjects.ObjectType.InstanceReference
    rc, objrefs = Rhino.Input.RhinoGet.GetMultipleObjects('Select block instances to reset', False, filter)
    if rc != Rhino.Commands.Result.Success: 
        return
    
    for objref in objrefs:
        irefObj = objref.Object()
        if isinstance(irefObj, Rhino.DocObjects.InstanceObject):
            idef = irefObj.InstanceDefinition
            dir = irefObj.InsertionPoint - Rhino.Geometry.Point3d.Origin
            xform = Rhino.Geometry.Transform.Translation(dir)
            iref = Rhino.Geometry.InstanceReferenceGeometry(idef.Id, xform)
            sc.doc.Objects.Replace(objref, iref, False)
    sc.doc.Views.Redraw()

if __name__ == "__main__":
    ResetBlock()

– Dale

[silvano]

@dale Many thanks for the quick reply. Maybe I did not explain correctly what I try to achieve or the script is not working as expected. Please see the below video. To my understanding, the rotation components of the object’s matrix did not change. Also xform holds the identity matrix (please see print of script).

Thanks again - Silvan