Visualization and Rendering

Currently, this addon supports the following 3 point cloud visualization options:

  • Representing the points with vertices of a Blender object

  • Visualizing the points with OpenGL (default)

  • Representing the points with a Blender particle system

_images/import_point_options.png

Each option has different advantages / disadvantages.

Option 1: Representing the points with vertices of a Blender object

If selected, the addon adds a blender object with a vertex for each point in the point cloud.

  • Advantage: Low computational costs for visualization / rendering.

  • Disadvantage: Contains no color information.

Option 2: Visualizing and rendering the points with OpenGL

If selected, the point cloud is shown in the Viewport using Blender’s OpenGL API. That means, there is no Blender object representing the points in the point cloud. The pose (i.e. rotation and translation) of the object can be changed by adjusting the corresponding “anchor” (i.e. a Blender empty object).

  • Advantage: Allows to show huge point clouds in the viewport - including color information.

  • Disadvantage: It is not possible to render these points with the render functions provided by Blender. However, this addon provides a panel to save/export OpenGL renderings of the points using an offscreen buffer or Blender’s screenshot operator (see image below).

_images/opengl_panel_export.png

Option 2a: Write results to disk with Blender’s offscreen buffer

Rendering the scene with Blender’s offscreen buffer renders (only!) the points drawn with Blender’s OpenGL API to disk. In order to render other elements such as cameras, image planes, meshes etc use Blender’s screenshot operator - see below.

Option 2b: Write results to disk with Blender’s screenshot operator

Since Blender’s screenshot operator renders all visible elements of the viewport to disk it is usually convenient to adjust the appearance.

In order to hide gridlines, axes etc. click on the Overlays button in Blenders 3D viewport and disable the corresponding options - see the image below.

_images/viewport_overlays_annotations.jpeg

To ensure that the reconstruction results are not occluded by Blender panels go to Edit / Preferences ... and uncheck the option Region Overlap - as shown in the following image. There, it is also possible to hide the Navigation Controls.

_images/editor_preferences_annotations.jpeg

After adjusting these options the viewport looks as follows.

_images/viewport_cleaned_annotations.jpeg

Option 3: Representing the points with a particle system

If selected, the point cloud is represented with two objects.

  • One object associated with a particle system, which represents the structure of the point cloud.

  • One object that defines the shape of the particles.

The color of the particles is defined by a single material as shown in the image below.

_images/particle_system_material.jpg

Note: The second input Value in the Divide node represents the number of particles in the point cloud.

  • Advantage: Contains color information, which can be rendered using Cycles.

  • Disadvantage: High computational costs for visualization / rendering, i.e. limited to medium-sized point clouds.

Sometimes Blender draws boundaries around the particles of the point cloud. In order to improve the visualization of the point cloud one can disable Extras under Overlays in the 3D view. The following image shows the corresponding options.

_images/disable_object_extras_overlay_annotation.jpg