IsoSurface

[MartinMcD]

Hello,

As far as I know its not possible to plot an IsoSurface in DIAdem, is anybody able to advise me otherwise please? I would be delighted to hear it is possible.  

Thanks,

Martin

[Brad_Turpin]

Hi Martin,

I believe that the answer is that DIAdem can plot an "IsoSurface", but first please explain what you mean, if possible with a picture.  Also, are you wanting this display in DIAdem VIEW or REPORT or both?  Also, what version of DIAdem are you using?

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[RAPatterson]

Hi Brad,

I have a description of this that may help. Not sure if it is what the original poster is looking for or not.

Isosurfaces seem to encompass the following features/interactions.

Start out with a 3-D (I would call it 4D myself) data set. That is, at each point (x,y,z) you have a value. Now imagine you have in your plot a cube, so as you are viewing the XYZ plot you can see the faces of the cube, these are slices of the data. If you zoom out these would be different slices because your view of the plot got wider. 

one interaction is to request a subset of data where the value = for example 3. All points would disappear except those where value=3. Those would all be the same color so you need a light source in the graph in order to be able to see anything.

another interaction is to choose a slice. Say I choose X=8. Now I can make a plot more like a surface plot where I can see Y,Z axis and colors representing the values at each Y,Z point.

Taking it another level deeper, I can choose perhaps Y=2. Now I have it down to a 2D plot where on the horizontal I have all the Z points and on the vertical I have the values.

I hope that's a good explanation without any visual aids. 

[RAPatterson]

Of course now I thought of a much easier explanation.

I want to plot f(x,y,z) where f is scalar. I want to apply a color map to the range of f. 

I also want to request only areas where f = some value v and have those points connected by an interpolated surface.

I also want to be able to hold x, y, or z in order to generate a sub-plot of sorts. For example, plot f(8,y,z) or plot f(8,2.5,z)

Richard

[MartinMcD]

Thank you for the responses.  Below is an image taken from the LabVIEW Biomedical Toolkit of what I was trying to achieve.  I realised this isn't possible in DIAdem but implemented my own version in LabVIEW by using the Marching Cubes algorithm to extract an isosurface from some xyz sensor data and displaying it in a 3D picture control, it works very nicely.

Thanks,

Martin

[Brad_Turpin]

Hi Guys,

Regarding your request, "I want to plot f(x,y,z) where f is scalar. I want to apply a color map to the range of f.", I have been asking DIAdem R&D for this for a lot of years with no success.  Neither can we truly plot a closed 3D surface in REPORT like the skull in your post.  It is possible to handle both these requests in VIEW by projecting the measured scalar values onto a 3D CAD model in VIEW, but it doesn't sound to me like you necessarily have a static object that you are investigating.  If the shape of the closed 3D object changes radically over the course of the measurement, then the VIEW CAD model approach can't keep up.  Note that VIEW can deform the starting 3D CAD model based on measurements, so if that could cover the shape changes, this might be a vaid way forward.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[RAPatterson]

Hi Brad,

This is also not completely solved in LabVIEW. The biomedical toolkit cannot display f(xyz) for all X, y, z, but only f(x,y,z)=v where v is some value. 

It would be good in both applications. One could imagine investigating any wavelike data such as radiated power coming from an antenna, or sound coming from a sound source, for example. Another example is wind speed data. If you have measured this data in enough different 3D locations, it would be useful to have a density plot that can be sliced up and be able to visualize the slices.

I give these examples because it is proof that this is no longer restricted to just MRI data.

Richard

[Brad_Turpin]

Hi Richard,

For field-based phenomena such as wind speed or Electric or Magnetic fields, DIAdem REPORT does offer full 3D vector display-- the ability to plot arrows at an (x,y,z) coordinate where the size fo the arrow is pulled from an independent magnitude channel.  Not a 4D color map, but an option to be aware of, still.

Brad Turpin

DIAdem Product Support Engineer
National Instruments