How to correctly extract nested objects from blocks with scaling/mirroring)

[p7q]

Hi everyone,

I’ve been working on modifying Lee Mac’s “Extract Nested Block” routine. @Lee Mac
By default, his code only extracts a nested block reference.
I have expanded it so that it can also extract non-block objects (lines, arcs, etc.) located inside a nested block reference.

The problem occurs when the selected object is inside one or more parent blocks that have been scaled or mirrored.
In these cases, the extracted object is placed in the wrong position in model space.

I know the “correct” way to solve this is to traverse the block reference hierarchy and apply all transformation matrices (scale, rotation, mirror) step by step until we reach world coordinates.
However, in large DWG files with many nested blocks, this approach becomes very slow and hurts performance significantly.

My question is:
Is there a more efficient way to get the final WCS coordinates of a nested object, including all scaling/mirroring effects from its parent blocks, without manually multiplying all transformation matrices?

Any suggestions or examples would be greatly appreciated.

Thanks in advance!

[SLW210]

Maybe something in my post or the one of Lee Mac's I linked...

 

 

[Lee Mac]

You can obtain the transformation matrix directly from an nentsel/nentselp call.

[Danielm103]

ARX would use AcDbBlockReference::blockTransform() to get the matrix, then call transformBy on the entity in one operation. You should be able to construct a vlax-tmatrix from the reference, then call vla-transformby on the objects you wish to transform.