<s>
Open	B-Language
Cascade	I-Language
Technology	I-Language
(	O
OCCT	O
)	O
,	O
formerly	O
called	O
CAS.CADE	O
,	O
is	O
an	O
open-source	B-Application
software	I-Application
development	O
platform	O
for	O
3D	O
CAD	B-Application
,	O
CAM	O
,	O
CAE	O
,	O
etc	O
.	O
</s>
<s>
that	O
is	O
developed	O
and	O
supported	O
by	O
Open	B-Language
Cascade	I-Language
SAS	I-Language
company	O
.	O
</s>
<s>
OCCT	O
is	O
a	O
full-scale	O
B-Rep	B-Algorithm
(	O
Boundary	B-Algorithm
representation	I-Algorithm
)	O
modeling	O
toolkit	O
.	O
</s>
<s>
OCCT	O
is	O
available	O
under	O
the	O
LGPL-2.1-only	B-Application
license	O
permitting	O
its	O
usage	O
in	O
open	O
source	O
and	O
proprietary	O
applications	O
.	O
</s>
<s>
CAS.CADE	O
(	O
abbreviated	O
from	O
Computer	O
Aided	O
Software	O
for	O
Computer	B-Application
Aided	I-Application
Design	I-Application
and	O
Engineering	O
)	O
was	O
originally	O
developed	O
in	O
the	O
early	O
1990s	O
by	O
Matra	O
Datavision	O
,	O
developer	O
of	O
Euclid	B-Algorithm
CAD	B-Application
software	I-Application
as	O
the	O
underlying	O
infrastructure	O
for	O
its	O
future	O
version	O
Euclid	B-Algorithm
Quantum	O
.	O
</s>
<s>
In	O
1998	O
the	O
company	O
abandoned	O
software	O
development	O
to	O
concentrate	O
on	O
services	O
,	O
and	O
most	O
of	O
the	O
software	O
development	O
facilities	O
were	O
sold	O
to	O
Dassault	O
Systèmes	O
,	O
developer	O
of	O
competing	O
CATIA	B-Algorithm
.	O
</s>
<s>
WebAssembly	B-Language
target	O
platform	O
support	O
(	O
including	O
WebGL	B-Library
viewer	O
)	O
.	O
</s>
<s>
Added	O
glTF	B-Language
2.0	O
and	O
OBJ	O
readers	O
.	O
</s>
<s>
Added	O
fast	O
HLR-alike	O
OpenGL	B-Application
rendering	O
mode	O
.	O
</s>
<s>
Path	B-Algorithm
Tracing	I-Algorithm
engine	O
improvements.Open	O
CASCADE	O
Technology	O
7.12016-11-25	O
-	O
-	O
OCAF	O
persistence	O
without	O
dynamically-loaded	O
plugins	O
.	O
</s>
<s>
Improved	O
STEP	O
AP242	O
support	O
,	O
including	O
PMI	B-Application
,	O
dimensions	O
and	O
annotations	O
.	O
</s>
<s>
TKOpenGl	O
now	O
uses	O
GLSL	O
programs	O
by	O
default.Open	O
CASCADE	O
Technology	O
7.02016-04-05	O
-	O
-	O
WOK	O
(	O
Workshop	O
Organization	O
Kit	O
)	O
has	O
been	O
replaced	O
by	O
CMake	B-Language
building	O
scripts	O
.	O
</s>
<s>
CDL	O
files	O
have	O
been	O
replaced	O
by	O
pre-generated	O
C++	B-Language
headers.Open	O
CASCADE	O
Technology	O
6.92015-05-126.9.12015-09-28	O
Introduced	O
"	O
Fuzzy	O
"	O
Boolean	O
operations	O
with	O
specified	O
global	O
tolerance	O
.	O
</s>
<s>
Improved	O
compatibility	O
with	O
OpenGL	B-Application
ES	I-Application
2.0.Open	O
CASCADE	O
Technology	O
6.82014-11-10	O
-	O
-	O
Added	O
support	O
of	O
UNICODE	O
(	O
UTF-8	O
)	O
filenames	O
.	O
</s>
<s>
Introduced	O
limited	O
OpenGL	B-Application
ES	I-Application
2.0	O
support	O
in	O
3D	O
viewer	O
.	O
</s>
<s>
Added	O
VIS	O
/	O
TKIVtk	O
component	O
providing	O
a	O
B-Rep	B-Algorithm
shape	O
presentation	O
builder	O
for	O
VTK	B-Language
viewer	O
.	O
</s>
<s>
Ray-Tracing	B-Algorithm
engine	O
has	O
been	O
switched	O
from	O
OpenCL	B-Application
to	O
GLSL	O
implementation.Open	O
CASCADE	O
Technology	O
6.72013-12-186.7.12014-04-30	O
License	O
has	O
been	O
changed	O
to	O
LGPL-2.1-only	B-Application
with	O
additional	O
exception	O
.	O
</s>
<s>
Built-in	O
GPU-accelerated	O
Ray-Tracing	B-Algorithm
rendering	O
engine	O
using	O
OpenCL.Open	O
CASCADE	O
Technology	O
6.62013-04-22	O
-	O
-Open	O
CASCADE	O
Technology	O
6.52011-04-046.5.52013-03-29Open	O
CASCADE	O
Technology	O
6.42010-09-30	O
-	O
-	O
Added	O
multi-threaded	O
mode	O
to	O
BRepMesh	O
algorithm	O
(	O
introduced	O
optional	O
TBB	O
library	O
support	O
)	O
.	O
</s>
<s>
Improved	O
rendering	O
performance	O
by	O
using	O
Vertex	B-Library
buffer	I-Library
object	I-Library
(	O
VBO	O
)	O
.	O
</s>
<s>
TKOpenGl	O
implementation	O
converted	O
from	O
C	O
to	O
C++	B-Language
classes	O
.	O
</s>
<s>
Improved	O
text	O
rendering	O
with	O
help	O
of	O
FTGL	O
and	O
FreeType	B-Application
libraries	O
.	O
</s>
<s>
Improved	O
algorithms	O
for	O
line-line	O
,	O
line-plane	O
and	O
plane-plane	O
intersection.Open	O
CASCADE	O
Technology	O
6.32008-09-036.3.12009-06-19Open	O
CASCADE	O
Technology	O
6.2	O
?	O
6.2.12007-12-06Open	O
CASCADE	O
Technology	O
6.12006-03-246.1.12006-10-16Open	O
CASCADE	O
Technology	O
5.2	O
?	O
5.2.42005-07-29Open	O
CASCADE	O
Technology	O
5.1	O
?	O
5.1.32004-04-23	O
"	O
Open	B-Language
CASCADE	I-Language
"	O
has	O
been	O
renamed	O
to	O
"	O
Open	B-Language
CASCADE	I-Language
Technology	I-Language
"	O
.Open	O
CASCADE	O
4.02001-12-11	O
-	O
-Open	O
CASCADE	O
3.02000-04-24	O
-	O
-Open	O
CASCADE	O
2.0	O
?	O
</s>
<s>
In	O
1999	O
Matra	O
Datavision	O
decided	O
to	O
publish	O
its	O
CAS.CADE	O
infrastructure	O
under	O
an	O
open-source	B-Application
model	O
under	O
the	O
Open	B-Language
CASCADE	I-Language
Technology	I-Language
Public	O
License	O
and	O
renamed	O
it	O
Open	B-Language
Cascade	I-Language
.	O
</s>
<s>
In	O
2000	O
,	O
a	O
separate	O
company	O
,	O
Open	B-Language
Cascade	I-Language
SAS	I-Language
,	O
was	O
created	O
to	O
make	O
business	O
around	O
Open	B-Language
Cascade	I-Language
.	O
</s>
<s>
Open	B-Language
Cascade	I-Language
SAS	I-Language
was	O
sold	O
in	O
2003	O
to	O
Principia	O
,	O
a	O
French	O
service	O
provider	O
corporation	O
,	O
and	O
then	O
in	O
2006	O
it	O
was	O
acquired	O
by	O
Euriware	O
Group	O
,	O
a	O
subsidiary	O
of	O
Areva	O
.	O
</s>
<s>
In	O
2004	O
,	O
software	O
was	O
renamed	O
to	O
Open	B-Language
Cascade	I-Language
Technology	I-Language
in	O
order	O
to	O
distinguish	O
it	O
from	O
the	O
name	O
of	O
the	O
company	O
itself	O
.	O
</s>
<s>
Open	B-Language
Cascade	I-Language
S.A.S.	O
</s>
<s>
Until	O
version	O
6.5.0	O
(	O
2011	O
)	O
,	O
only	O
minor	O
and	O
major	O
versions	O
were	O
publicly	O
available	O
,	O
while	O
intermediate	O
(	O
maintenance	O
)	O
releases	O
were	O
accessible	O
only	O
to	O
customers	O
of	O
Open	B-Language
Cascade	I-Language
S.A.S.	O
</s>
<s>
In	O
March	O
2011	O
,	O
Thomas	O
Paviot	O
initiated	O
a	O
fork	O
of	O
the	O
then	O
most	O
recent	O
publicly	O
available	O
version	O
6.5.0	O
of	O
Open	B-Language
Cascade	I-Language
library	O
.	O
</s>
<s>
The	O
initiative	O
is	O
called	O
Open	B-Language
Cascade	I-Language
Community	O
Edition	O
.	O
</s>
<s>
In	O
December	O
2011	O
,	O
Open	B-Language
Cascade	I-Language
installed	O
a	O
web	O
portal	O
for	O
external	O
contributors	O
and	O
made	O
its	O
Mantis	B-Application
Bug	I-Application
Tracker	I-Application
and	O
further	O
Git	B-Application
repository	O
publicly	O
available	O
(	O
read-only	O
GitHub	B-Application
mirror	O
has	O
been	O
established	O
in	O
'	O
2020	O
)	O
.	O
</s>
<s>
According	O
to	O
the	O
statements	O
on	O
the	O
new	O
website	O
,	O
external	O
contributors	O
from	O
the	O
Open	O
Source	O
Community	O
are	O
encouraged	O
to	O
participate	O
in	O
the	O
development	O
of	O
Open	B-Language
Cascade	I-Language
Technology	I-Language
,	O
i.e.	O
</s>
<s>
register	O
bugs	O
directly	O
in	O
the	O
bugtracker	B-Application
,	O
make	O
contributions	O
to	O
the	O
code	O
after	O
signing	O
a	O
Contributor	O
License	O
Agreement	O
,	O
etc	O
.	O
</s>
<s>
Since	O
18	O
December	O
2013	O
with	O
version	O
6.7.0	O
Open	B-Language
Cascade	I-Language
Technology	I-Language
is	O
available	O
under	O
the	O
LGPL-2.1-only	B-Application
with	O
additional	O
exception	O
.	O
</s>
<s>
Versions	O
before	O
that	O
were	O
licensed	O
under	O
the	O
"	O
Open	B-Language
Cascade	I-Language
Technology	I-Language
Public	O
License	O
"	O
which	O
was	O
not	O
compatible	O
with	O
the	O
GPL	B-License
and	O
was	O
considered	O
non-free	O
by	O
the	O
Fedora	O
project	O
.	O
</s>
<s>
)	O
,	O
acceleration	O
data	O
structures	O
(	O
BVH	B-Data_Structure
Trees	I-Data_Structure
)	O
and	O
vector/matrix	B-Language
math	I-Language
used	O
by	O
other	O
Modules	O
.	O
</s>
<s>
Modeling	O
Data	O
:	O
supplies	O
data	O
structures	O
to	O
represent	O
2D	O
and	O
3D	O
geometric	O
primitives	O
(	O
analytical	O
curves	O
:	O
Line	O
,	O
Circle	O
,	O
Ellipse	O
,	O
Hyperbola	O
,	O
Parabola	O
,	O
Bézier	O
,	O
B-spline	B-Algorithm
,	O
Offset	O
;	O
analytical	O
surfaces	O
:	O
Plane	O
,	O
Cylinder	O
,	O
Cone	O
,	O
Sphere	O
,	O
Torus	O
,	O
Bézier	O
,	O
B-spline	B-Algorithm
,	O
Revolution	O
,	O
Extrusion	O
,	O
Offset	O
)	O
and	O
their	O
compositions	O
into	O
B-Rep	B-Algorithm
models	O
.	O
</s>
<s>
Modeling	O
Algorithms	O
:	O
contains	O
a	O
vast	O
range	O
of	O
geometrical	O
and	O
topological	O
algorithms	O
(	O
intersection	O
,	O
Boolean	O
operations	O
,	O
surface	B-Algorithm
meshing	I-Algorithm
,	O
fillets	O
,	O
shape	O
healing	O
)	O
.	O
</s>
<s>
Visualization	O
(	O
rendering	O
)	O
:	O
provides	O
interactive	O
services	O
for	O
displaying	O
geometry	O
in	O
3D	O
Viewer	O
;	O
implements	O
a	O
compact	O
OpenGL	B-Application
/	O
OpenGL	B-Application
ES	I-Application
renderer	O
,	O
supporting	O
conventional	O
Phong	O
,	O
real-time	O
PBR	O
metal-roughness	O
shading	O
models	O
as	O
well	O
as	O
interactive	O
Ray-Tracing/Path	O
-Tracing	O
engine	O
.	O
</s>
<s>
Data	O
Exchange	O
:	O
provides	O
possibility	O
to	O
import/export	O
various	O
CAD	B-Application
formats	O
.	O
</s>
<s>
STEP	O
,	O
IGES	O
,	O
glTF	B-Language
,	O
OBJ	O
,	O
STL	O
and	O
VRML	B-Application
are	O
supported	O
natively	O
.	O
</s>
<s>
Extended	O
Data	O
Exchange	O
(	O
XDE	O
)	O
components	O
rely	O
on	O
a	O
unified	O
XCAF	O
document	O
definition	O
,	O
which	O
includes	O
an	O
assembly	O
structure	O
of	O
CAD	B-Application
shapes	O
,	O
color/name/material/metadata/layer	O
attributes	O
as	O
well	O
as	O
other	O
supplementary	O
information	O
like	O
PMI	B-Application
.	O
</s>
<s>
DRAW	O
Test	O
Harness	O
:	O
implements	O
a	O
scripting	O
interface	O
to	O
OCCT	O
algorithms	O
based	O
on	O
Tcl-interpreter	O
for	O
interactive	O
usage	O
,	O
automating	O
processes	O
,	O
prototyping	O
applications	O
and	O
testing	O
purposes	O
.	O
</s>
<s>
Workshop	O
Organization	O
Kit	O
(	O
WOK	O
)	O
is	O
Open	B-Language
Cascade	I-Language
development	O
environment	O
,	O
which	O
has	O
been	O
designed	O
to	O
allow	O
a	O
large	O
number	O
of	O
developers	O
to	O
work	O
on	O
a	O
product	O
getting	O
advantage	O
of	O
common	O
reference	O
version	O
shared	O
over	O
the	O
local	O
network	O
.	O
</s>
<s>
The	O
Open	B-Language
CASCADE	I-Language
IFC	B-Application
Import	O
SDK	O
provides	O
applications	O
with	O
the	O
capability	O
of	O
reading	O
BIM	B-Architecture
data	O
from	O
files	O
in	O
IFC	B-Application
format	O
.	O
</s>
<s>
This	O
allows	O
visualization	O
and	O
manipulation	O
of	O
building	O
geometries	O
and	O
CAD	B-Application
designs	I-Application
.	O
</s>
<s>
External	O
tools	O
are	O
available	O
to	O
convert	O
from	O
Open	B-Language
CASCADE	I-Language
to	O
IFC	B-Application
as	O
well	O
.	O
</s>
<s>
Several	O
CAD	B-Application
programs	I-Application
rely	O
on	O
Open	B-Language
CASCADE	I-Language
Technology	I-Language
including	O
:	O
</s>
<s>
FreeCAD	B-Language
an	O
open	O
source	O
,	O
3D	O
parametric	O
modeler	O
,	O
with	O
support	O
for	O
building	B-Architecture
information	I-Architecture
modeling	I-Architecture
,	O
finite-element-method	O
(	O
FEM	O
)	O
,	O
and	O
Python	B-Language
scripting	O
.	O
</s>
<s>
SALOME	B-Application
an	O
open	B-Application
source	I-Application
platform	I-Application
for	O
pre	O
-	O
and	O
post-processing	O
for	O
numerical	O
simulation	O
.	O
</s>
<s>
KiCad	B-Language
an	O
open	O
source	O
suite	O
for	O
electronic	O
design	O
automation	O
(	O
EDA	O
)	O
.	O
</s>
<s>
Gmsh	B-Language
an	O
open	O
source	O
finite-element	O
mesh	O
(	O
FEM	O
)	O
generator	O
.	O
</s>
<s>
Since	O
version	O
3.0	O
,	O
Gmsh	B-Language
supports	O
full	O
constructive	O
solid	O
geometry	O
features	O
,	O
based	O
on	O
OCCT	O
.	O
</s>
<s>
FORAN	B-Algorithm
an	O
integrated	O
CAD/CAM/CAE	O
system	O
developed	O
by	O
SENER	O
for	O
the	O
design	O
and	O
production	O
of	O
practically	O
any	O
naval	O
ship	O
and	O
offshore	O
unit	O
.	O
</s>
<s>
FORAN	B-Algorithm
uses	O
OCCT	O
since	O
V80R2.0	O
release	O
for	O
working	O
with	O
analytical	O
surfaces	O
.	O
</s>
<s>
IFC	B-Application
Open	O
Shell	O
,	O
a	O
Python	B-Language
library	O
for	O
working	O
with	O
IFC	B-Application
data	O
.	O
</s>
<s>
Uses	O
Open	B-Language
CASCADE	I-Language
internally	O
to	O
convert	O
the	O
implicit	O
geometry	O
in	O
IFC	B-Application
files	O
into	O
explicit	O
geometry	O
that	O
any	O
software	O
CAD	B-Application
or	O
modelling	O
package	O
can	O
use	O
.	O
</s>
