<p>a) about </p>

<blockquote>
  <p>Is B-REP a mesh that only represents a boundary [..] ?</p>
</blockquote>

<p>B-Rep contains more information, see <a href="https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/model/b-rep.html" rel="nofollow noreferrer">here</a>:</p>

<blockquote>
  <p>There are two types of information in a B-rep: topological and
  geometric. Topological information provide the relationships among
  vertices, edges and faces similar to that used in a wireframe model.
  In addition to connectivity, topological information also include
  orientation of edges and faces. Geometric information are usually
  equations of the edges and faces.</p>
</blockquote>

<p>b) about </p>

<blockquote>
  <p>and therefore ready to be printed</p>
</blockquote>

<p>it is need not only check that the model is correct (no lack of a face, no wrong face normals, ...) but also that is valid for a 3d printer (no "floating" parts, addition of supports, ...).</p>

<p>Finally, recall the model is not what drives the printer, the printer is controlled by the machine instructions, usually gcode. Thus, the usual evolution is: parts description (.scad, ...), model format (.stl, ...) and machine instructions (.gcode).</p>

CC BY-SA 3.0
2017-08-20T10:08:11.897Z
2017-08-20T10:08:11.897Z
pasaba por aqui
<p>before a mesh can be printed it needs to be 'repaired'. According to most tutorials that is including making the shape close and removing inner shapes. Reading through B-REP in Wikipedia there is no layman term or explanation how it differs form the traditional polygonal mesh create for example from scanning or exporting from CAD. Is B-REP a mesh that only represents a boundary and therefore ready to be printed?</p>

<3d-models><cad><repair>
Is B-REP a ready to print mesh
Rott
# Is B-REP a ready to print mesh

(Asked by: username_0 on 2017-08-19)

before a mesh can be printed it needs to be 'repaired'. According to most tutorials that is including making the shape close and removing inner shapes. Reading through B-REP in Wikipedia there is no layman term or explanation how it differs form the traditional polygonal mesh create for example from scanning or exporting from CAD. Is B-REP a mesh that only represents a boundary and therefore ready to be printed?

**Tags:** 3d-models, cad, repair

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## 1 answers

### Answer by username_1 on 2017-08-20. Score: 1 | Accepted answer

a) about

> Is B-REP a mesh that only represents a boundary [..] ?

B-Rep contains more information, see [here](https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/model/b-rep.html):

> There are two types of information in a B-rep: topological and
> geometric. Topological information provide the relationships among
> vertices, edges and faces similar to that used in a wireframe model.
> In addition to connectivity, topological information also include
> orientation of edges and faces. Geometric information are usually
> equations of the edges and faces.

b) about

> and therefore ready to be printed

it is need not only check that the model is correct (no lack of a face, no wrong face normals, ...) but also that is valid for a 3d printer (no "floating" parts, addition of supports, ...).

Finally, recall the model is not what drives the printer, the printer is controlled by the machine instructions, usually gcode. Thus, the usual evolution is: parts description (.scad, ...), model format (.stl, ...) and machine instructions (.gcode).


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