Topic: Base Point Location of Block Reference

[kwarmington]

I am having trouble getting the "Base Point" of a Block Reference in autocad. I am not sure if base point is the correct terminology or not.

If I perform a LIST command on a Block Reference in autocad the values for the location are the same as if I use the BlockReference.Position in .NET i.e.

                  External reference
                at point, X=128170.18580000  Y=44629.83387360  Z=26037.43318039
   X scale factor: 1.00000000
   Y scale factor: 1.00000000
   Z scale factor: 1.00000000
Extrusion direction relative to UCS:
                   X=0.00000000  Y=-0.25881731  Z=0.96592629

However if i use a LISP command (entget (car (entsel))) I get different values in the dxf code 10 position. The values that I get here, are the ones that I want to get in .NET.
 
i.e.
Select object: ((-1 . <Entity name: -51963e98>) (0 . "INSERT") (5 . "29F5")
(102 . "{ACAD_XDICTIONARY") (360 . <Entity name: -51963e90>) (102 . "}") (330 .
<Entity name: -4011f2f8>) (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 .
"ADE_TEMP") (100 . "AcDbBlockReference") (2 . "T61-5-2-0103") (10 128170.0
49848.1 13599.3) (41 . 1.0) (42 . 1.0) (43 . 1.0) (50 . 1.5708) (70 . 0) (71 .
0) (44 . 0.0) (45 . 0.0) (210 0.0 -0.258817 0.965926))



Does anyone know the equivalent .NET command to get the Block References original insertion point (base point) which is the same as a the DXF 10 code?

In VBA I have noticed there is a object.BasePoint property however I do not know how to convert this to .NET.

Cheers,

Kate

[Bryco]

Position?

[kdub_nz]

Position !

[kwarmington]

Thanks for the replies -

I have had a look around today and I think my question is now -

How do I translate the position of the block reference to what it was before the blockRef.Normal was applied.

So I place the block Reference at the correct position
I change the block reference's extrusion using Blockref.Normal which in turn gives it a new position.

I need the original position of the block for my comparision. So i need to somehow "undo" the extrusion I have applied without manipulating the block.

Im nearly certain I am doing all my calcualtion in WCS and position is in WCS, but I also dont really know what I'm doing

I can post code if it will help in anyway.

Cheers,

Kate

[SEANT]

If the ultimate goal is to place a BlockRef at a particular point with a particular normal then one method would be to reverse the order of operation.  For instance,

Insert the Reference at 0,0,0

Set Refernce.Normal

Set Reference.Position

[T.Willey]

Would you have to transform the point by the inverse of the block's matrix ( to get it back to WCS )?

Point3d.TransformBy( BlockRef.BlockTransform.Inverse() );

[SEANT]

Ah, yes. . . . the situation does seem more concerned with a post insertion query.   The OP expands further on the request here:

http://discussion.autodesk.com/forums/thread.jspa?threadID=726226&tstart=0

[Kerry]

Looks like Tony is helping you additionally elsewhere.
Be sure to post back with the resolution



edit: oops simultaneous posting

[kwarmington]

Hi Everyone,

Thanks for all your help. I have just posted again over on the AutoDesk Discussion group. I have posted some sample drawings and some sample code.

Still not entirely sure what is going on. Hopefully I can solve this today - going on holidays for 2 weeks, and work will not be happy if its not fixed!

http://discussion.autodesk.com/forums/thread.jspa?threadID=726226&tstart=0

[kwarmington]

Thanks to SeanT my problem has been solved

over on the autocad site he posted -

Code: [Select]

Point3d zero = new Point3d();

Point3d GCTp3d = zero - zero.TransformBy(br.BlockTransform.Inverse()).GetAsVector();//Crux

GCTp3d = GCTp3d.RotateBy(br.Rotation, new Vector3d(0.0,0.0,1.0),zero);

which worked fantastically!

Thank you!

[SEANT]

Quite predictably, Tony did ultimately post the best solution.  I’m happy, however, to have provided an interim solution.  I may even be so bold as to say that my offering helped focus the problem.