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222 lines
7.9 KiB
Plaintext
222 lines
7.9 KiB
Plaintext
/*!
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\page blsurf_hypo_page BLSURF Parameters hypothesis
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\n BLSURF Parameters hypothesis works only with <b>BLSURF</b> 2d
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algorithm. This algorithm is a commercial software.
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\image html blsurf_parameters.png
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<ul>
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<li><b>Name</b> - allows to define the name of the hypothesis (BLSURF
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Parameters by default).</li>
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<li><b>Physical Mesh</b> - if is set to "Custom", allows to set size
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of mesh elements to generate in <b>User size</b> field.
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</li>
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<li><b>User size</b> - size of mesh elements to generate. </li>
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<li><b>Max Physical Size</b> - is an upper limit of mesh element size. </li>
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<li><b>Min Physical Size</b> - is a lower limit of mesh element size. </li>
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<li><b>Geometrical mesh</b> - if is set to "Custom", allows to set
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mesh element deflection from curves and surfaces and element
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size change rate in <b>Angle Mesh S</b>, <b>Angle Mesh C</b> and
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<b>Gradation</b> fields correspondingly. These fields control
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computation of element size, so called <i>geometrical size</i>, conform to
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the surface geometry considering local curvatures. \n
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The eventual element size at each point will be minimum of <b>User
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size</b>, if given, and the <i>geometrical size</i>. </li>
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<li><b>Angle Mesh S</b> - maximal allowed angle in degrees at a mesh
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node between the mesh face and the tangent to the geometrical surface. </li>
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<li><b>Angle Mesh C</b> - maximal allowed angle in degrees at a mesh
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node between the mesh edge and the tangent to the geometrical curve. </li>
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<li><b>Max Geometrical Size</b> - is an upper limit of <i>geometrical size</i>.</li>
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<li><b>Min Geometrical Size</b> - is a lower limit of <i>geometrical size</i>.</li>
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<li><b>Gradation</b> - maximal allowed ratio between the lengths of
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two adjacent edges. </li>
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<li><b>Allow Quadrangles</b> - to create quadrilateral elements.</li>
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<li><b>Patch independent</b> - if this box is checked on, geometrical
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edges are not respected and all geometrical faces are meshed as one
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hyper-face.</li>
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\image html blsurf_parameters_advanced.png
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<li><b>Topology</b> - allows creation of a conform mesh on a shell of
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not sewed faces.
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<ul>
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<li>"From CAD" means that mesh conformity is assured by conformity
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of a shape.</li>
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<li>"Pre-process" and "Pre-process++" let BLSURF software
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pre-process the geometrical model to eventually produce a conform
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mesh. </li>
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</ul>
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<li><b>Verbosity level</b> - Defines the percentage of "verbosity" of
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BLSURF [0-100].</li>
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<li><b>Add option</b> - provides a choice of multiple advanced
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options, each of which, if selected, appear in a table where you can
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enter a value of the option and edit it later.</li>
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<li><b>Clear option</b> - removes option selected in the table.
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</ul>
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\n
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Commonly usable options are following. The name <i>diag</i> stands there for
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the diagonal of the bounding box of the geometrical object to mesh.
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<ul>
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<li><b>topo_eps1</b> (real) - is the tolerance level inside a CAD
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patch. By default is equal to <i>diag</i> <20> 10-4. This tolerance is used to
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identify nodes to merge within one geometrical face when \b Topology
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option is to pre-process. Default is <i>diag</i>/10.0.</li>
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<li><b>topo_eps2</b> (real) - is the tolerance level between two CAD
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patches. By default is equal to <i>diag</i> <20> 10-4. This tolerance is used to
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identify nodes to merge over different geometrical faces when
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\b Topology option is to pre-process. Default is <i>diag</i>/10.0.</li>
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<li>\b LSS (real) - is an abbreviation for "length of sub-segment". It is
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a maximal allowed length of a mesh edge. Default is 0.5.</li>
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<li>\b frontal (integer)
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<ul>
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<li> 1 - the mesh generator inserts points with an advancing front method.</li>
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<li> 0 - it inserts them with an algebraic method (on internal edges). This method is
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slightly faster but generates less regular meshes. </li>
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</ul>
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Default is 0.</li>
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<li>\b hinterpol_flag (integer) - determines the computation of an
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interpolated value <i>v</i> between two points <i>P1</i> and <i>P2</i> on a
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curve. Let <i>h1</i> be the value at point <i>P1,</i> <i>h2</i> be the value at point
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<i>P2,</i> and <i>t</i> be a parameter varying from 0 to 1 when moving from <i>P1
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to</i> <i>P2</i> .
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<ul>
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<li>0 - the interpolation is linear: <i>v = h1 + t (h2 - h1 )</i></li>
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<li>1 - the interpolation is geometric: <i>v = h1 * pow( h2/h1, t)</i></li>
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<li>2 - the interpolation is sinusoidal: <i>v = (h1+h2)/2 +
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(h1-h2)/2*cos(PI*t)</i></li>
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</ul>
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Default is 0.</li>
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<li>\b hmean_flag (integer) - determines the computation of the mean of several
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values:<ul>
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<li>-1 - the minimum is computed.</li>
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<li>0 or 2 - the arithmetic mean computed.
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<li>1 - the geometric mean is computed.</li>
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</ul>
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Default is 0.</li>
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<li>\b CheckAdjacentEdges, \b CheckCloseEdges and \b CheckWellDefined
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(integers) - give number of calls of equally named subroutines the
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purpose of which is to improve the mesh of domains having narrow
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parts. At each iteration,\b CheckCloseEdges decreases the sizes of the
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edges when two boundary curves are neighboring,\b CheckAdjacentEdges
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balances the sizes of adjacent edges, and \b CheckWellDefined checks if
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the parametric domain is well defined. Default values are 0.</li>
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<li>\b CoefRectangle (real)- defines the relative thickness of the rectangles
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used by subroutine \b CheckCloseEdges (see above). Default is 0.25.</li>
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<li>\b eps_collapse (real) - if is more than 0.0, BLSURF removes
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curves whose lengths are less than \b eps_collapse. Here, to obtain an
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approximate value of the length of a curve, the latter is arbitrarily
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split into 20 edges. Default is 0.0.</li>
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<li>\b eps_ends (real) - is used to detect curves whose lengths are very
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small, which sometimes constitutes an error. A message is printed
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if<i> fabs(P2-P1) < eps_ends</i>, where <i>P1</i> and <i>P2</i> are the
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extremities of a curve. Default is <i>diag</i>/500.0.</li>
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<li>\b prefix (char) - is a prefix of the files generated by
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BLSURF. Default is "x".</li>
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<li>\b refs (integer) - reference of a surface, used when exporting
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files. Default is 1.</li>
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</ul>
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\n
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The following advanced options are not documented and you can use them
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at your own risk.
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\n\n Interger variables:
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<ul>
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<li> addsurf_ivertex</li>
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<li> background </li>
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<li> coiter </li>
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<li> communication </li>
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<li> decim </li>
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<li> export_flag </li>
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<li> file_h </li>
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<li> gridnu </li>
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<li> gridnv </li>
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<li> intermedfile </li>
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<li> memory </li>
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<li> normals </li>
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<li> optim </li>
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<li> pardom_flag </li>
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<li> pinch </li>
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<li> rigid </li>
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<li> surforient </li>
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<li> tconf </li>
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<li> topo_collapse </li>
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</ul>
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Real variables:
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<ul>
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<li> addsurf_angle </li>
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<li> addsurf_R </li>
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<li> addsurf_H </li>
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<li> addsurf_FG </li>
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<li> addsurf_r </li>
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<li> addsurf_PA </li>
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<li> angle_compcurv </li>
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<li> angle_ridge </li>
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<li> eps_pardom </li>
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</ul>
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String variables:
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<ul>
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<li> export_format </li>
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<li> export_option </li>
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<li> import_option </li>
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</ul>
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\n
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Currently BLSURF plugin has the following limitations.
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<ul>
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<li>Mesh contains inverted elements, if it is based on shape,
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consisting of more than one face (box, cone, torus...) and if
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the option "Allow Quadrangles (Test)" was checked before
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computation.</li>
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<li>SIGFPE exception is raised at trying to compute mesh, based on
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box, with checked option "Patch independent".</li>
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<li>It has been found out that BLSURF algorithm can't be used as a
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local algorithm (on sub-meshes) and as a provider of low-level
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mesh for some 3D algorithms because BLSURF mesher (and
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consequently plugin) does not provide information on node
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parameters on edges (U) and faces (U,V). For example the
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following combinations of algorithms are impossible:
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<ul>
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<li> global MEFISTO or Quadrangle(mapping) + local BLSURF;</li>
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<li> BLSUFR + Projection 2D from faces meshed by BLSURF;</li>
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<li> local BLSURF + Extrusion 3D;</li>
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</ul>
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</li>
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</ul>
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*/
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