Table of Contents
Point cloud
GroIMP provides tools and functions to analyze and manipulate point clouds
I/O Point Cloud
The import formats both for files and object representation in GroIMP presented in this tutorial are mostly coming from the plugin Pointcloud. See here to see how install plugins in GroIMP. The wiki is up to date with the version 1.7 of the plugin.
GroIMP support two ways of defining a point cloud object:
- As an array: the points coordinates are stored in the array, and the object is considered as one node in the project graph.
- As a graph: each point is built in a node of the project graph. This representation enables links between nodes and possible meshes imported (e.g. ply files can support point, line and faces).
Other point cloud tutorials:
Point Cloud Tools in the Graphical User Interface
Note: This tutorial is based on the plugin “PointCloud” that you can get either through the Plugin manager (within Groimp) or by downloading the jar here.
All features in this overview are available when a 3D project or an RGG project is opened in GroIMP. The functions work independently from XL scripts and are only based on the objects that are currently available in the 3D view.
The Edit Point Cloud menu is located inside the Objects menu. The Fit Point Cloud to Object menu is located inside the Objects menu and (there) inside the Edit Point Cloud menu.
Warning: In the current version of GroIMP, the shortcut Alt + O does not work. This is due to the fact that O is used twice and the wrong menu entry is focused by default. If the objects menu is already open, the other shortcuts (→ C → [custom key]) work as described.
Point Cloud Tools in XL and Headless Mode
Note: This tutorial is based on the plugin “PointCloud” that you can get either through the Plugin manager (within Groimp) or by downloading the jar here.
This overview contains the list of available java functions concerning point cloud import, clustering, splitting, merging, and export. They can be used in the java code (by future developers) and in XL code (by GroIMP users). They can also be used in headless mode. Parameters are always passed when the functions are called in code, they are never requested in a graphical window. All functions can be used when the class de.grogra.imp3d.pointcloud.PointCloudTools is imported with the following java/XL command:
import de.grogra.imp3d.pointcloud.PointCloudTools;
All functions are static functions in the PointCloudTools class and not available as object based functions like pointcloud.function().
The given point clouds and returned point clouds are of the type de.grogra.imp3d.objects.PointCloud and fully compatible to the other 3D objects.
All objects that are created by functions in the PointCloudTools class are not added to the RGG graph. They only exist as objects in the code context and can be added to the graph manually if required.
Using a mesh cloud as a high resolution organ
This tutorial uses a ply file of a leaf with points and meshes to simulate a small branch. The leaf is transformed and added several times to a branch model, to simulate leaf growth and light absorption.
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| The rendered result of the example branch |
The example model can be found in the GroIMP example explorer (File/Example projects) under Point cloud/branch.
Using a point cloud to validate a simulation
The idea is to take a point cloud of a measured tree and 'move it over' it on the simulated tree to see how similar the tree and the measurements are. In the following, the point cloud (shown in the figure below) has been artificially created and therefore fits the tree very well.
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| Generated example point cloud and two models with 99% and 85% accuracy |
The example model can be found in the GroIMP gallery
Point Cloud Tools: Algorithms and Math
Note: This is based on the plugins “PointCloud” and “PointCloud-Shapefitting” you get them through the Plugin manager. Because formulas can not be displayed here efficiently, we would recommend to read the belonging practical reports for more information about the math behind the point cloud features. In case of interest, please contact the GroIMP developer team.