All entries for May 2006

May 30, 2006

Tuesday's Progress

Spent a few hours with haptic rendering today:

  • Managed to load new models on H3D.
  • Created x3d that has separate geormetries for haptic and graphic
  • Enabled the stereo vision and it worked very well
  • Deformation is still unrealistic due to the slow update

Problems:

  • "Haptic holes" on the surface – maybe due to the update rate
  • slow update due to indexedFaceSet. Have to try indexedTriangleSet to reduce computation load

Added a new diagram to my presentation slide. Updated some points. Looking forward to the conference on Thursday.


May 28, 2006

Haptic data

Haptic data to look at:

1. stiffness
2. damping
3. friction

1 - 3: vectors or matrices corresponding to individual points or faces on the model

4. equations and variables

  • deformation energy equation
  • spring mass model – support between surfaces?
  • finite element model
  • particle/geometrical model

4 - should take note of the variables corresponding to the object properties, young's modulus, poisson ratio, attribute matrices and vectors

5. Operational and non–operational – flagging method to tag the area

  • boundary vertices/edges
  • operational vertices that will be deformed
  • maybe extract these points realtime via interaction with model
  • allow iteration/traversing/parsing based on the fixed level of detail when touching one point on surface– hence in the area of interest, a more complex calculation for both force and visual, the rest will use simpler method that is less realistic
  • this will allow realtime deformation and force calculation efficiently

These data, variables and attributes should correspond to the mesh data: vertices, faces, material data, haptic node, spring…

This will be the basis to the overall ontology in the end for testing.


May 26, 2006

Mal de tête

Splitting headache after attempting to create a deformable organ mesh using H3D ontop of C++, OpenGL and OpenHaptics. Progress for the day:

i) fixed DLL problem for Phantomiolab42
ii) surface properties for heart mesh (now heart.x3d is touchable)
iii) simple deformation upon interaction with heart surface mesh (use of deformShape and coordinateDeform node)
iv) The use of plasticity to control level of defeormation – permanent or elastic

The resulting deformation is too simple and too unrealistic. The triangular meshes are visible when deformed. Intracomponent collision is not supported by H3D API. Will need to create new nodes:

i) inter/intra object collision
ii) mesh separation but join deformation and force effect
iii) node to read database

Will need to find out more about:

i) shading
ii) tesselation?? Delaunay??
iii) force effect and spring effect
iv) spring mass or finite element
v) better organisation of material data for the triangles or the object as a whole

Anyone familiar with deformation???

All praise to Jesus!!! I pray for more breakthroughs, inspiration, wisdom, strength and motivation!!!!


This is funny

link

May 25, 2006

Experiment itinery

Experiment detail (26/05-26/06)

1.Look into openhaptics and H3D

  • Test program
  • Modify program
  • Learn materials, collision and deformation
  • Note the apis needed

2.explore X3D

  • explore structure
  • explore connection with haptic
  • explore connection with python
  • create object and components on 3Dstudiomax then convert to x3d

3.explore subcomponents – create dummy hierarchy and dummy tissue types

  • based it on standard hierarchy structure (anatomy ontology)
  • create hierarchy design
  • explore material calculation – search on net or biomedical, etc
  • create arrays or matrices or structures to contain attributes

4.explore database in C++ and python

  • create access database referring to attributes and components
  • test query and update in C++ and python

5.explore Node in H3D

  • create new node to read database
  • create node to read data from OBJ?
  • node to create deformation to the mesh
  • node to traverse triangles to embed correct material properties

6.analyse and decide openhaptics or H3D

7.explore collision and deformation more

  • design force equations
  • design multiple collision of subcomponents

May 24, 2006

Is ur PASSWORD long enough? ;)

The Perfect Password :

A woman was helping her husband set up his computer, and

at the appropriate point in the process, told him that he would now need to

enter a password.

Something he will use to log on to the computer.

The husband was in a rather amorous mood and figured he

would try for the shock effect to bring this to his wife's attention. So,

when the computer asked him to enter his password, he made it plainly obvious to his wife that he was keying in:

P… E… N… I… S…

His wife fell off her chair laughing when the computer replied:

***PASSWORD REJECTED. NOT LONG ENOUGH


May 22, 2006

The inspiring SANDI THOM

Check her sound up: link

Longer version of Punk Rocker here: link


Monday progress

Went through the openhaptics example on haptic viewer. Had a bit of a problem with the compiler but managed to configure the include, lib and src files. Thanks to Dr Jilin for some pointers on how to do it.

I modified the program to include haptics material instead of using default values set by the system.

i) array to hold the values for stiffness, damping and friction. Declared the variable and a new get fuction in haptic viewer doc class header file. Implemente the function get Material in the CPP file. The variable is initialised in the cpp file as well (after retrieving the OBJ file containing the geometries).

ii) The getmaterial will be used in hapticviewer view to return values to the the haptic material embedder. The drawHL had to be modified to accept material array.

iii) ideas: (example)

an object = component 1 + component 2 + component 3 …+component n

component 1= (a% of M1 + b% of M2 + c% of M3…+ N% of Mtt)/tt

M = material
tt=total material type

Hence each component can be linearly described by the average of material values interms of stiffness, damping, friction. Have to look at values such as young and poisson.

A+b+c…+N = 100%

iv) have to look at subcomponents and how to do it recursively from main object to sumcomponents to sub sub components, etc…


Monday blues…

Feeling rather uninspired today… woke up late… then I braved through the rain to uni… checked my email and the scripture for the day…

Do not fret because of evil men or be envious of those who do wrong; for like the grass they will soon wither, like green plants they will soon die away. Trust in the LORD and do good; dwell in the land and enjoy safe pasture. Delight yourself in the LORD and he will give you the desires of your heart. Commit your way to the LORD; trust in him and he will do this: He will make your righteousness shine like the dawn, the justice of your cause like the noonday sun. Psalm 37:1-6 NIV


May 21, 2006

Strictly come dancing

Writing about web page http://www.bbc.co.uk/strictlydancefever/competitors/darren_lana.shtml

My favourite Darren and Lana were amazing in their first dance tonight. The managed to get 36 points. Last week, they forked out 38, the best ever point!! I do hope that they will win it. But it all depends on the public vote. Please please vote for them haha :)


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