# Is it possible to define a cross section in a .prc file?

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You can use the OdPrcFromCurvesSurface class, which implements the PRC\_TYPE\_SURF\_FromCurves type of .prc format and then do the following:

```
eval_point = first_curve.evaluate(param.u) + second_curve.evaluate(param.v) – origin;
```

Another way is to use a NURB surface (if you have code to convert a cross section surface to a NURB surface).

Please see the OdPrcCreate example application (Prc/Examples/OdPrcCreate):

- To get sample code for creating an object of the OdPrcFromFromCuresSurface class (example case is "BrepModelFromCurves").
- To get sample code for creating an object of the OdPrcNurbsSurface class (example case is "BrepModelNURBS").