Blender Foundation: Blender 2.x BF release: Detail: 24665 mathutils.Matrix initialization is counter-intuitive and generates bugs

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[#24665] mathutils.Matrix initialization is counter-intuitive and generates bugs

Date:
2010-11-11 17:26 Priority:
3

State:
Closed

Submitted by:
Dominique Lorre (dlorre) Assigned to:
Campbell Barton (campbellbarton)

Category:
Python Status:
Fixed / Closed

Relates to: Duplicates:

Patches:

Summary:
mathutils.Matrix initialization is counter-intuitive and generates bugs

Detailed description

Given the following code:
mat = mathutils.Matrix((1,2,3,4),(5,6,7,8),(9,10,11,12),(13,14,15,16))
print(str(mat))

The result is:

Matrix((1.000000, 5.000000, 9.000000, 13.000000), (2.000000, 6.000000, 10.000000
, 14.000000), (3.000000, 7.000000, 11.000000, 15.000000), (4.000000, 8.000000, 1
2.000000, 16.000000))

Wether or not this is intended or a bug, it is what causes the 3DS import bug reported earlier since the values are not initialized in the right order.

Followup

Message

Date: 2010-11-11 18:26
Sender: Tom Edwards
As a workaround, you can transpose() it.

Date: 2010-11-11 19:16
Sender: Ton Roosendaal
Campbell: shouldn't python code print out matrices in same row-collumn order as you define it?

Date: 2010-11-11 19:31
Sender: Dominique Lorre
@Tom Edwards: You are correct.
using transpose() at line 609 of import_3ds.py instead of invert() fixes the issue reported earlier.

#contextMatrix_rot.resize4x4()
#print "MTX"
#print contextMatrix_rot
contextMatrix_rot.transpose()
#print contextMatrix_rot
#contextMatrix_tx = mathutils.Matrix.Translation(0.5 * Blender.mathutils.Vector(data[9:]))
#contextMatrix_tx.invert()

Date: 2010-11-12 04:08
Sender: Campbell Barton
fixed in svn, the error was with printing.

The printing was incorrect, also gave it nicer formatting.

>>> from mathutils import Matrix
>>> Matrix()
Matrix((1.0, 0.0, 0.0, 0.0),
(0.0, 1.0, 0.0, 0.0),
(0.0, 0.0, 1.0, 0.0),
(0.0, 0.0, 0.0, 1.0))

regarding 3ds problem, replied here:
http://projects.blender.org/tracker/index.php?func=detail&aid=24626&group_id=9&atid=264

Date: 2010-11-12 05:14
Sender: Campbell Barton
fixed in svn, the error was with printing.

The printing was incorrect, also gave it nicer formatting.

>>> from mathutils import Matrix
>>> Matrix()
Matrix((1.0, 0.0, 0.0, 0.0),
(0.0, 1.0, 0.0, 0.0),
(0.0, 0.0, 1.0, 0.0),
(0.0, 0.0, 0.0, 1.0))

regarding 3ds problem, replied here:
http://projects.blender.org/tracker/index.php?func=detail&aid=24626&group_id=9&atid=264

Attached Files:

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Changes:

Field	Old Value	Date	By

close_date	2010-11-12 05:14	2010-11-12 05:14	campbellbarton
Resolution	Approved	2010-11-12 04:08	campbellbarton
close_date	2010-11-12 04:08	2010-11-12 04:08	campbellbarton
status_id	Open	2010-11-12 04:08	campbellbarton
Category	None	2010-11-11 19:16	ton
Resolution	None	2010-11-11 19:16	ton
assigned_to	none	2010-11-11 19:16	ton