A camera allows to define a specific point of view for a rendering. It defines which portion of a scene is visible in the rendered image.
The rendering process in the external renderer will always need one (and only one) camera as an input: the active camera. That being said:
Cameras are optional in FreeCAD rendering projects. Indeed, if no camera is defined in a project, the current point of view in FreeCAD viewport will be used instead to create a virtual camera on-the-fly and export it to the renderer.
More than one camera can also be added into a project. In this case, all the cameras will be exported to the renderer, which will retain one (usually the last one) as active camera.
Please note that Visibility matters also: only visible cameras (meaning their
Visibility parameters are True) will be exported to the renderer.
Tip: if you want to make various renderings of a scene from different points of
views (left view, right view etc.), you can create the corresponding cameras,
add them all to your project, and then play on Visibility parameters, keeping
only one camera visible at a time, to get each of the renderings.
The general method to add a camera to your rendering project is the following:
- Create the camera object: press
- If necessary, tweak the camera's position and orientation in your scene
- Add a view of the camera in your project. This is a mandatory step to
have the camera eventually exported to the renderer! Use
button, like for
objects...
Please note that the camera will be created using the current point of view in FreeCAD viewport (i.e. the current internal Coin camera). Thus painful reorientation/repositioning effort can be avoided by carefully positioning your point of view in viewport before creating your camera. You may also prefer to set view to perspective in the viewport, which will usually be closer to final rendering.
The camera will be represented in viewport by the following symbol:
Render Camera records the internal camera parameters used in FreeCAD viewport. This viewport relies on Pivy/Coin, a 3D-rendering library implementing the Open Inventor standard. This is why we refer you to Open Inventor and Coin camera documentations for more details about Render Camera parameters.
You will find, in Camera context menu, a few features to help positioning and orienting a Camera:
Set GUI to this camera: resets the GUI camera (the camera from which the scene is seen in FreeCAD viewport) to the selected Camera.Set this camera to GUI: sets the selected Camera to the GUI camera.Point at...: allows to orient the camera so that it looks at a specific object. Trigger this action, click on the target object in the viewport, and the camera will be automatically oriented towards the selected object.
You can access the context menu by right-clicking on the Camera in the tree view.