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IDProjectCategoryView StatusLast Update
0004744FreeCADBugpublic2021-12-20 10:13
Reporterandr.syn Assigned Tochennes  
Status closedResolutionfixed 
OSWindowsOS Version10 
Product Version0.20 
Fixed in Version0.20 
Summary0004744: STEP Export/Import Colors Override
DescriptionIn STEP file exported from FC colors are not the same as in original FCStd file.
This can be verified when STEP file is opened with another program.
When this STEP file is opened with FC, colors look as they were in original FCStd.
So, colors are being changed in both Export and Import processes.

Discussed here:
Steps To ReproduceJust export any model into STEP with colors and then open it with another program, for example, Open Cascade CAD Assistant:

I use Altium Designer.

In attached picture Cubes_FreeCAD.png there are 3 cubes as they look on the FreeCAD screen.
The RGB values for each cube are as follows:
Grey: 128, 128, 128.
Orange: 210, 120, 20.
Blue: 0, 50, 160.

Then I export these 3 cubes into STEP file and open it in Altium Designer (adding them on the PCB surface).

In attached Cubes_AD.png there are 2 rows of cubes. Upper one is this STEP file from FreeCAD. In the bottom row are 3 cubes made in Altium Designer directly with the same RGB values.

Colors in upper row (FreeCAD) and bottom row (AD) are altogether different.
STEP model from FreeCAD looks much lighter (brighter). But it is not just lighter. In some cases relations between RGB components are changed (they are not simply multiplied by the same coefficient).

And similar color transformation occurs in reverse, when we import (open) in FreeCAD a STEP model made with another program. But in this case colors in FreeCAD, in opposite, become darker than they should be.
Additional InformationThis issue relates to FC 0.19 and 0.20, FC 0.18 does not have this issue.
TagsNo tags attached.
FreeCAD InformationOS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.25645 (Git)
Build type: Release
Branch: master
Hash: 37d9757399b4c2ec30318eb88d7cd7c508246345
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: Russian/Russia (ru_RU)



2021-09-11 00:06


Cubes_FreeCAD.png (8,419 bytes)   
Cubes_FreeCAD.png (8,419 bytes)   
Cubes_Altium.png (30,407 bytes)   
Cubes_Altium.png (30,407 bytes)   


2021-10-02 09:10

reporter   ~0015957

it could be related to OCC release version...
[OCCT] 7.5.0 recently additions -> 0029902: Data Exchange, XCAF - provide extended Material definition for visualization purposes


2021-10-10 02:39

administrator   ~0015963

Potential fix in PR 5098 from @realthunder:


2021-12-16 19:52

administrator   ~0016103

Fix merged.


2021-12-20 10:13

manager   ~0016116

Just for the records: the fix is also in our latest stable release FreeCAD 0.19.3

Issue History

Date Modified Username Field Change
2021-09-11 00:06 andr.syn New Issue
2021-09-11 00:06 andr.syn File Added: Cubes_FreeCAD.png
2021-09-11 00:06 andr.syn File Added: Cubes_Altium.png
2021-10-02 09:10 easyw-fc Note Added: 0015957
2021-10-10 02:39 chennes Note Added: 0015963
2021-10-10 02:40 chennes Assigned To => chennes
2021-10-10 02:40 chennes Status new => assigned
2021-12-16 19:52 chennes Status assigned => closed
2021-12-16 19:52 chennes Resolution open => fixed
2021-12-16 19:52 chennes Fixed in Version => 0.20
2021-12-16 19:52 chennes Note Added: 0016103
2021-12-20 10:13 uwestoehr Note Added: 0016116