From 32285411da24346ef93cead9aef90c0b0fc18e0e Mon Sep 17 00:00:00 2001 From: Luca Heltai Date: Tue, 1 May 2018 16:34:45 +0200 Subject: [PATCH] Fixed intro. --- examples/step-54/doc/intro.dox | 63 +++++++++++++++++----------------- 1 file changed, 31 insertions(+), 32 deletions(-) diff --git a/examples/step-54/doc/intro.dox b/examples/step-54/doc/intro.dox index 353b4ff0da..4a1c84eb6c 100644 --- a/examples/step-54/doc/intro.dox +++ b/examples/step-54/doc/intro.dox @@ -16,19 +16,19 @@ your geometries. In some of the previous tutorial programs (step-1, step-3, step-5, step-6 and step-49 among others) we have learned how to use the mesh refinement methods provided in deal.II. These tutorials have shown how to employ such tools to -produce a fine grid for a single simulation, as done in step-3; or to start -from a coarse grid and carry out a series of simulations on adaptively refined -grids, as is the case of step-6. Regardless of which approach is taken, the -mesh refinement requires a suitable geometrical description of the -computational domain boundary in order to place, at each refinement, the new -mesh nodes onto the boundary surface. For instance, step-5 shows how to assign -a circular shape to the boundary of the computational domain, so that the -faces lying on the boundary are refined onto the circle. step-53 shows how to -do this with a boundary defined by experimentally obtained data. But, at -least as far as elementary boundary shapes are concerned, deal.II really only -provides circles, spheres, boxes and various combinations. In this tutorial, -we will show how to use a set of classes developed to import arbitrary CAD -geometries, assign them to the desired boundary of the computational domain, +produce a fine grid for a single simulation, as done in step-3; or to start from +a coarse grid and carry out a series of simulations on adaptively refined grids, +as is the case of step-6. Regardless of which approach is taken, the mesh +refinement requires a suitable geometrical description of the computational +domain boundary in order to place, at each refinement, the new mesh nodes onto +the boundary surface. For instance, step-5 shows how creating a circular grid +automatically attaches a circular manifold object to the computational domain, +so that the faces lying on the boundary are refined onto the circle. step-53 +shows how to do this with a Manifold defined by experimentally obtained data. +But, at least as far as elementary boundary shapes are concerned, deal.II really +only provides circles, spheres, boxes and other elementary combinations. In this +tutorial, we will show how to use a set of classes developed to import arbitrary +CAD geometries, assign them to the desired boundary of the computational domain, and refine a computational grid on such complex shapes. @@ -53,29 +53,28 @@ U.S. National Bureau of Standards published in 1980 the Initial Graphics Exchange Representation (IGES) neutral file format, which is used in this example. -

The boundary projector classes

+

The CAD boundary projector classes

-To import and interrogate CAD models, the deal.II library contains a series of -wrapper functions for the OpenCASCADE open source library for CAD -modeling. These functions allow to import IGES files into OpenCASCADE native -objects, and wrap them inside a series of Manifold classes. +To import and interrogate CAD models, the deal.II library implements a series of +wrapper functions for the OpenCASCADE open source library for CAD modeling. +These functions allow to import IGES files into OpenCASCADE native objects, and +wrap them inside a series of Manifold classes. Once imported from an IGES file, the model is stored in a TopoDS_Shape, which is the generic topological entity defined in -the OpenCASCADE framework. From a TopoDS_Shape, it is then -possible to access all the sub-shapes (such as vertices, edges and faces) -composing it, along with their geometrical description. In the deal.II -framework, the topological entities composing a shape are used to create -a corresponding Manifold representation. In Step-6 we saw how to build a -SphericalManifold and assign it to a set of faces (or cells, for co-dimension -1) of a Triangulation, to have cells and faces refined on a sphere or circle. -The functions of the CAD modeling interface have been designed to retain the -same structure, allowing the user to build a projector object using the -imported CAD shapes, maintaining the very same procedure we use with -SphericalManifold, i.e., assigning such projector object to cells, faces or -edges of a coarse mesh. At each refinement cycle, the new mesh nodes will be -then automatically generated by projecting a midpoint of an existing object -onto the specified geometry. +the OpenCASCADE framework. From a TopoDS_Shape, it is then possible +to access all the sub-shapes (such as vertices, edges and faces) composing it, +along with their geometrical description. In the deal.II framework, the +topological entities composing a shape are used to create a corresponding +Manifold representation. In step-6 we saw how to build a hyper sphere, which is +automatically assigned a SphericalManifold to its boundary faces, to have them +refined on a sphere or on a circle. The functions of the CAD modeling interface +have been designed to retain the same structure, allowing the user to build a +projector object using the imported CAD shapes, maintaining the same procedure +we used in other tutorial programs, i.e., assigning such projector object to +cells, faces or edges of a coarse mesh. At each refinement cycle, the new mesh +nodes will be then automatically generated by projecting a midpoint of an +existing object onto the specified geometry. Differently from a spherical or circular boundary, a boundary with a complex geometry poses problems as to where it is best to place the new nodes created -- 2.39.5