- in continuation of #2565 (rotationCentre for surface output formats)
it is helpful to also support READ_IF_PRESENT behaviour for the
'origin' keyword.
This can be safely used wherever the coordinate system definition
is embedded within a sub-dictionary scope.
Eg,
dict1
{
coordinateSystem
{
origin (0 0 0); // now optional here
rotation ...;
}
}
but remains mandatory if constructed without a sub-dict:
dict2
{
origin (0 0 0); // still mandatory
e1 (1 0 0);
e3 (0 0 1);
}
With this change, the "transform" sub-dictionary can written
more naturally:
formatOptions
{
vtk
{
scale 1000; // m -> mm
transform
{
rotationCentre (1 0 0);
rotation axisAngle;
axis (0 0 1);
angle -45;
}
}
}
ENH: simplify handling of "coordinateSystem" dictionary lookups
- coordinateSystems::NewIfPresent method for optional entries:
coordSysPtr_ = coordinateSystem::NewIfPresent(mesh, dict);
Instead of
if (dict.found(coordinateSystem::typeName, keyType::LITERAL))
{
coordSysPtr_ =
coordinateSystem::New
(
mesh_,
dict,
coordinateSystem::typeName
);
}
else
{
coordSysPtr_.reset();
}
ENH: more consistent handling of priorities for binModels, forces (#2598)
- if the dictionaries are overspecified, give a 'coordinateSystem'
entry a higher prioriy than the 'CofR' shortcuts.
Was previously slightly inconsistent between the different models.
- Can specify
```
transform
{
origin (1 2 3);
rotation none;
}
```
instead of the longer form
```
transform
{
origin (1 2 3);
e1 (1 0 0);
e3 (0 0 1);
}
```
COMPAT: remove old (pre-1812) Euler and STARCD keywords
- use "angles", remove old compat name "rotation"
as clutter and possible confusion with "coordinate rotation"
STYLE: remove coordinate rotation move constructors
- an unnecessary holdover from older code.
- wrap command-line retrieval of fileName with an implicit validate.
Instead of this:
fileName input(args[1]);
fileName other(args["someopt"]);
Now use this:
auto input = args.get<fileName>(1);
auto other = args.get<fileName>("someopt");
which adds a fileName::validate on the inputs
Because of how it is implemented, it will automatically also apply
to argList getOrDefault<fileName>, readIfPresent<fileName> etc.
- adjust fileName::validate and clean to handle backslash conversion.
This makes it easier to ensure that path names arising from MS-Windows
are consistently handled internally.
- dictionarySearch: now check for initial '/' directly instead of
relying on fileName isAbsolute(), which now does more things
BREAKING: remove fileName::clean() const method
- relying on const/non-const to control the behaviour (inplace change
or return a copy) is too fragile and the const version was
almost never used.
Replace:
fileName sanitized = constPath.clean();
With:
fileName sanitized(constPath);
sanitized.clean());
STYLE: test empty() instead of comparing with fileName::null
- as part of the cleanup of dictionary access methods (c6520033c9)
made the dictionary class single inheritance from IDLList<entry>.
This eliminates any ambiguities for iterators and allows
for simple use of range-for looping.
Eg,
for (const entry& e : topDict))
{
Info<< "entry:" << e.keyword() << " is dict:" << e.isDict() << nl;
}
vs
forAllConstIter(dictionary, topDict, iter))
{
Info<< "entry:" << iter().keyword()
<< " is dict:" << iter().isDict() << nl;
}
Previously the coordinate system functionality was split between
coordinateSystem and coordinateRotation. The coordinateRotation stored
the rotation tensor and handled all tensor transformations.
The functionality has now been revised and consolidated into the
coordinateSystem classes. The sole purpose of coordinateRotation
is now just to provide a selectable mechanism of how to define the
rotation tensor (eg, axis-angle, euler angles, local axes) for user
input, but after providing the appropriate rotation tensor it has
no further influence on the transformations.
--
The coordinateSystem class now contains an origin and a base rotation
tensor directly and various transformation methods.
- The origin represents the "shift" for a local coordinate system.
- The base rotation tensor represents the "tilt" or orientation
of the local coordinate system in general (eg, for mapping
positions), but may require position-dependent tensors when
transforming vectors and tensors.
For some coordinate systems (currently the cylindrical coordinate system),
the rotation tensor required for rotating a vector or tensor is
position-dependent.
The new coordinateSystem and its derivates (cartesian, cylindrical,
indirect) now provide a uniform() method to define if the rotation
tensor is position dependent/independent.
The coordinateSystem transform and invTransform methods are now
available in two-parameter forms for obtaining position-dependent
rotation tensors. Eg,
... = cs.transform(globalPt, someVector);
In some cases it can be useful to use query uniform() to avoid
storage of redundant values.
if (cs.uniform())
{
vector xx = cs.transform(someVector);
}
else
{
List<vector> xx = cs.transform(manyPoints, someVector);
}
Support transform/invTransform for common data types:
(scalar, vector, sphericalTensor, symmTensor, tensor).
====================
Breaking Changes
====================
- These changes to coordinate systems and rotations may represent
a breaking change for existing user coding.
- Relocating the rotation tensor into coordinateSystem itself means
that the coordinate system 'R()' method now returns the rotation
directly instead of the coordinateRotation. The method name 'R()'
was chosen for consistency with other low-level entities (eg,
quaternion).
The following changes will be needed in coding:
Old: tensor rot = cs.R().R();
New: tensor rot = cs.R();
Old: cs.R().transform(...);
New: cs.transform(...);
Accessing the runTime selectable coordinateRotation
has moved to the rotation() method:
Old: Info<< "Rotation input: " << cs.R() << nl;
New: Info<< "Rotation input: " << cs.rotation() << nl;
- Naming consistency changes may also cause code to break.
Old: transformVector()
New: transformPrincipal()
The old method name transformTensor() now simply becomes transform().
====================
New methods
====================
For operations requiring caching of the coordinate rotations, the
'R()' method can be used with multiple input points:
tensorField rots(cs.R(somePoints));
and later
Foam::transformList(rots, someVectors);
The rotation() method can also be used to change the rotation tensor
via a new coordinateRotation definition (issue #879).
The new methods transformPoint/invTransformPoint provide
transformations with an origin offset using Cartesian for both local
and global points. These can be used to determine the local position
based on the origin/rotation without interpreting it as a r-theta-z
value, for example.
================
Input format
================
- Streamline dictionary input requirements
* The default type is cartesian.
* The default rotation type is the commonly used axes rotation
specification (with e1/e2/3), which is assumed if the 'rotation'
sub-dictionary does not exist.
Example,
Compact specification:
coordinateSystem
{
origin (0 0 0);
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
Full specification (also accepts the longer 'coordinateRotation'
sub-dictionary name):
coordinateSystem
{
type cartesian;
origin (0 0 0);
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
}
This simplifies the input for many cases.
- Additional rotation specification 'none' (an identity rotation):
coordinateSystem
{
origin (0 0 0);
rotation { type none; }
}
- Additional rotation specification 'axisAngle', which is similar
to the -rotate-angle option for transforming points (issue #660).
For some cases this can be more intuitive.
For example,
rotation
{
type axisAngle;
axis (0 1 0);
angle 30;
}
vs.
rotation
{
type axes;
e2 (0 1 0);
e3 (0.5 0 0.866025);
}
- shorter names (or older longer names) for the coordinate rotation
specification.
euler EulerRotation
starcd STARCDRotation
axes axesRotation
================
Coding Style
================
- use Foam::coordSystem namespace for categories of coordinate systems
(cartesian, cylindrical, indirect). This reduces potential name
clashes and makes a clearer declaration. Eg,
coordSystem::cartesian csys_;
The older names (eg, cartesianCS, etc) remain available via typedefs.
- added coordinateRotations namespace for better organization and
reduce potential name clashes.
