Rendering camera

This command allows to create a conical camera by indicating the position of the eye, the point of view, the type of lens and the features of the image to be calculated (size, rendering scale).

This type of camera also allows you to use a 2D background image to superimpose a 3D design.

It could be used with the realistic rendering command.

Creation stages / Use:

Select the Visualization > Cameras > Rendering Camera... command from the drop-down menu.

Enter the output width (width of the image produced by the realistic rendering calculation).
Enter the output height (height of the image produced by the realistic rendering calculation).
Enter a rendering scale (if 100%, the generated image will have the same dimensions as the width/height values. If 75%, the generated image will be 0.75 times smaller).
Enter a preview scale (size of the preview available in the rendering calculation window of the realistic rendering command).
Select the type of camera to create: Field of view, Focal length or Calibration (in this last case, an image must be selected beforehand).
Specify the camera origin.
Specify the target point.
Specify the up direction.

In the contextual menu in the graphics area, the Cameras menu allows you to call a rendering camera. The view is then that of the camera where only the zoom can be modified (by maintaining the centring view), it will not be possible to move or rotate the scene. It allows you to easily visualize the image that will be produced by the realistic rendering, image contained in the camera frame. The use of a rendering camera is preferable when the graphic area is divided into several views, allowing to adjust more easily the disposition of the object in the field of vision of the camera or by moving the origin and the target in another view while seeing

the effect of this redefinition in a view attached to the rendering camera.

A rendering camera of type Field of view or Focal length could not be changed in a rendering camera of type Calibration.

Available options:

Field of view:

When the lens definition type used is Field of view, enter the angle value.

Whatever the format of the camera, an angle of view of 45° always corresponds to a normal focal length.

Focal length:

When the lens definition type used is Focal length, enter:

Sensor width.
Sensor height.
Focal length.

These data correspond to photo lens settings.

A focal length of 50mm is a normal focal length in 24×36.

Calibration:

This option allows you to create a camera resulting from the integration of a 3D design marker in a photo.

This type of camera will only be available if an image has been used in the Background image menu at the top of the command.

Specify a background image.
Select Calibration as lens definition
Give the frame to match with the image
Calibrate the frame on the image from the Calibrate... button.

Position the frame in the image.
Number of vanishing points:

Specify the number of vanishing points useful for the definition of the camera. Here 2 vanishing points have been used, characterized by the red lines and green lines .

Vanishing axes:

Give the direction of the vanishing axes and position them on the image. Here the first vanishing axis has the direction X+ and the corresponding lines are positioned at the bottom of the bar and the bottom of the ceiling return. The second vanishing axis is on Y- and it is the window frame that is used to position the lines.

The vanishing lines have the same color as their reference axis (X, Y or Z) and are marked with a label for the first vanishing axis and for the second.

Reference distance:

Give the direction of the reference distance and position its segment on the image.

Give the real value of this segment (measured in your 3D design). This data is used to apply a scale factor to match the design to the image.

Here the direction is based on the X axis and the top of the bar has been used as the reference distance of 5m.

Reference distance anchor at origin:

By checking this option, the reference direction will necessarily pass through the origin of the coincidence frame.

Principal point:

This point indicates where the camera points. In the case of a photo, it is in the center of the image. But if the photo is resized and that we keep only a part of it, this point is no longer in the center of the partial image. In this case, the camera must be off-center and the perspective is askew .

Rectangle mode:

With this mode, available only if with 2 vanishing points, it is possible to define the four vanishing lines by a simple rectangle in the frequent case where rectangular areas are visible in perspective on the image.

3D guide:

To visually help you in these settings, you can add a guide like a box or plane.

Dim image:

Here again, to facilitate these settings, it is possible to dim the image to bring out the vanishing lines.

Sensor data:

Available only with 1 vanishing point. Allows to specify the width and height of the sensor as well as the focal length.

The image will also be visible in the realistic rendering mode if the rendering camera is used as the current camera in the graphics area. . And it will be of course used in the calculation of the photorealistic image of the Realistic rendering command.

Modifications / Additional information:

A rendering camera can be edited from the Cameras folder of the entities tree or in contextual mode in the graphics area from the black triangle available on the camera frame.