Woolz Image Processing  Version 1.7.5
_WlzCMeshElm3D Struct Reference

A single 3D tetrahedral mesh element. Typedef: WlzCMeshElm3D. More...

Data Fields

int idx
 
unsigned int flags
 
struct _WlzCMeshFace face [4]
 
struct _WlzCMeshCellElm3DcElm
 
void * prop
 

Detailed Description

A single 3D tetrahedral mesh element. Typedef: WlzCMeshElm3D.

The following diagram depicts a mesh element, viewed from above with the apex (node n0) pointing towards the viewer. From this view, face f3 is at the rear of the tetrahedron.

                                        O n1                         
                                       /|\                   
                                      / | \                  
                                     /  |  \                 
                                    /   |   \                
                                   /    |    \    f3          
                                  /     |     \  /           
                                 /      |      \/            
                                /       |      .\            
                               /        |     .  \            
                              /         |    .    \                  
                             /          |   .      \                 
                            /           O           \                
                           /      f1   / \    f0     \               
                          /          /  n0 \          \              
                         /         /         \         \             
                        /        /             \        \            
                       /       /                 \       \            
                      /      /                     \      \            
                     /     /                         \     \            
                    /    /              f2             \    \            
                   /   /                                 \   \            
                  /  /                                     \  \           
                 / /                                         \ \           
             n3 O-----------------------------------------------O n2        

The relationship between nodes and faces depicted in this diagrap is used in constructing new mesh elements.

The tetrahedron can be opened a net and viewed looking at the directed edges uses associated with the faces from outside the element surface as shown below:

                                    n1                                
   n0 O-----------------------------O-----------------------------0 n0  
       \    ---------------------> / \    -------------------->  /    
        \ %         e0            / % \ %         e1            /     
         \ \                   / / /   \ \                  /  /      
          \ \                 / / /   \ \ \                /  /       
           \ \               / / /     \ \ \              /  /        
            \ \     f0      / / /       \ \ \     f1     /  /        
             \ \ e2     e1 / / /         \ \ \ e1    e0 /  /         
              \ \         / / /           \ \ \        /  /           
               \ \       / / /     f3      \ \ \      /  /             
                \ \     / / /  e0       e1  \ \ \    /  /               
                 \ \   / / /                 \ \    /  /                 
                  \   / / /                   \ \  %  /                   
                   \ % /           e2          % \   /                    
                    \ /  <--------------------    \ /                       
                     O-----------------------------O                         
                   n2 \ %  -------------------->  / n3                
                       \ \         e1            /                    
                        \ \                   / /                     
                         \ \                 / /                      
                          \ \               / /                       
                           \ \     f2      / /                        
                            \ \           / /                         
                             \ \ e0   e2 / /                          
                              \ \       / /                           
                               \ \     / /                            
                                \ \   / /                            
                                 \   / /                              
                                  \ % /                               
                                   \ /                                
                                    O                                 
                                   n0                                 

Each mesh element has four faces and each face has three directed edges, with the edges directed counter clockwise (when viewed from outside the mesh element) away from their nodes.

Indexing of faces, edge uses and nodes in 3D elements.
Face Edge Use Node
0 0 0
0 1 1
0 2 2
1 0 0
1 1 3
1 2 1
2 0 0
2 1 2
2 2 3
3 0 1
3 1 1
3 2 3

The face opposite a node, or node opposite a face can easily be found using: \(f + n = 3\), where \(f\) is the face and \(n\) is the node.

Field Documentation

unsigned int _WlzCMeshElm3D::flags
struct _WlzCMeshCellElm3D* _WlzCMeshElm3D::cElm

First cell element from which all other cell elements can be reached using the next pointer.

Referenced by WlzCMeshNewNod3D().

void* _WlzCMeshElm3D::prop

Element properties.


The documentation for this struct was generated from the following file: