150 Components

This demo exposes an X3DOM scene of 150 Sphere elements which are spatially indexed under the same 3D R-tree instance. Their sporadically distribution in 3D space creates a highly overlapping structure, forcing R-tree operations to traverse more subtrees than usual and achieve increased time costs.

(1) Initialize a 3D R-tree data structure to populate city buildings

(2) Display the generated 3D R-tree in X3DOM canvas (optional)

Choose any of the following viewpoints to easily navigate and zoom in/out

POINT QUERY

Place a query point in the scene to search for intersecting objects


X:
N/A

Y:
N/A

Z:
N/A




REGION/WINDOW QUERY

Attach a moveable rectangular parallelepiped area to retrieve overlapping objects


Modify the predefined size of the presented search area

Size X:
Size Y:
Size Z:



k-NN QUERY

Attach a moveable Cone element to retrieve its k-th nearest neighbors


X:
N/A

Y:
N/A

Z:
N/A

Define k-NN sample



SPATIAL RELATIONS

Calculate spatial relations between indexed objects



No. of relations

Coordinates input above after the creation of the R-tree structure were also used in the baseline case study, which involved a set of comparison operations without indexing capabilities. Point query was represented by an intersection criterion aimed to validate the given coordinates against each 3D object's bounding box, while a containment check was applied for region query case. On the other hand, k-NN measurement took place with a sequential recording of the Euclidean distances between the given coordinates and each 3D object, followed by a sorting in an ascending order in order to retrieve the k-closest. Finally, the deduction of spatial relations was made through an exponential search for all possible combinations between scene's 3D objects.

POINT QUERY

X:
N/A

Y:
N/A

Z:
N/A




REGION/WINDOW QUERY

Size X:
Size Y:
Size Z:


k-NN QUERY

X:
N/A

Y:
N/A

Z:
N/A




SPATIAL RELATIONS



No. of relations

Tei of Crete
Multimedia Content Lab Master Thesis by Konstantinos Kontakis