### Composite

- brep
  - Editing brep
  - Brep special commands
  - Rotation brep
  - Sweep brep
  - Creating brep object from truetype font
- NURBSmesh
- bezierblob
- CSG
  - intersection
  - subtractunion

#### brep

brep (Boundary representation) objects are solid objects formed by polygon. brep objects may be internal or external to .rt file. When you create a brep object you must include a model from the current directory.

##### Editing brep

You can move the vertices of a brep object. You should edit only inline brep objects .

Follow this steps:

1) Select a brep object.

2) Click on a vertex. A red square will appear.

3) Move the mouse in the new position and press `m' key.

##### Brep special commands

Use command "Edit|Object|Special". You will see the special menu for brep object.

Info

give information on the status of the brep object. This can tell you if the model is an inline model or if it is an external model ( in this case you will see also the file name).

Include In Scene

if the brep object is external, include a copy inside the .rt file. Files with inline models can became very large.

External Model

if the model is internal, you can save the model in a brep file.

Save

refresh the brep file ( only for external models ).

##### Rotation brep

> To build a brep you need to rotate a polyline around an axis. The rotation axis will be the Y axis. To see the axis press the F12 key or use Command|Axis. The polyline can be open or close. ( Use the special menu for open or close a polyline ). If the polyline is open you need that the first and the last point of the curve are on the Y axis, like in the picture. The first and the last point can not be exactly on the axis but near; the program will move them for you. The curve can be closed: All the points must be all positive or all negative. To make a rotation of a polyline you must choose "rotation" from the special menu of the polyline. The program will ask for the name of the new object, the number of subdivisions and the angle of rotation.

##### Sweep brep

> You may build a sweep brep only from a closed polyline. Choose "sweep" from the special menu of the polyline. The program will ask for the name and the height of the new object. It is possible to build more complex sweep object, with hole, following a path or with deformations. Before you have to create a shape to sweep. This must be a group of polylines. Follow this procedure: 1) Create a new layer with the name of the shape ( es. test_shape ). 2) Select the new layer 3) Select the top view 4) Draw the external and the internal polyline ( you must draw one external polyline and one or more internal polyline or no internal polyline ). 5) Use command Layer|Group to create group "test_shape". 6) Now in the default layer, draw a polyline that will be the sweep path ( in the front or side view ) with name "path1". 7) Select the group "test_shape" and call the special menu of the object. 8) Choose "Sweep". 9) In the dialog box give a name to the brep object, and choose "path1" in the path listbox. At the end you will have a sweep brep. You can also deform the shape when it follow the path. You need a deformation graph ("deformgraph").

##### Creating brep object from truetype font

You must follow this steps:

1) the option ConvertText must be on, in Option|General

2) Create a layer ( es. `new_text' ) and select it.

3) Choose `Insert|Text' command, then select the font and the character dimension ( greater than 100 for better resolution ).

4) insert you text string

At this time you should see the text on the top view ( if not, try to press `o' key sometimes on top view ). Each letter of the string is composed by one or more polyline. Now you can create a brep object using sweep.

5) Use layer|group command

6) Execute `Edit|Object|Special' then choose sweep.

#### NURBSmesh

#### bezierblob

4.3.2.4

You can create blob objects.

You need an external program to do it :Winblob. You can find it at:

ftp://ftp.povray.org/pub/povray/utilities/general/winblobs.zip

Create a blob object and save it in .blb file format, then use command "Edit|Object|Create" and choose "blob".

#### CSG

##### intersection

##### subtractunion

4.3.2.5.3