[50%] Logarithmic scale for scalars + normal visualization

[Dimitri]

Hi Daniel,

ok this is soon Christmas, so it's time to make a wish list ;-)

. Something that could be extremely useful : remember the scales (displayed and saturation) and coloramp parameters used to display one type of scalar (provided that the user has modified the default one). Because, when when one wants to switch between 2 scalars on the same cloud, the same color scheme is applied to the 2, and it has to be modified by hand. Obviously, it is always possible to do that by cloning the data but at some point you risk having too many clouds lying around.
Alternatively, a system of predefined scale parameters files could do the trick : Once the user is happy with a scale parameter (including all display parameters : viewing angle, scalar name, etc....) it could be saved in a file, and reloaded afterwards for any session or any scalar. This would be indeed very, very useful. This could even remember all the display characteristics for all the scalar of a given file : this way you load your point cloud with scalar attached, you load your display characteristics file, et voila ! Everything is ready for inspection.

. would it be possible to have a box that can be ticked to change from linear to logarithmic scale for the scalar color scheme ? I've got patterns of deformation going from a few mm to a few meters in the same scene and I'd be great to have a way to capture these on a single image (rather than doing one image with high deformation, and another with low deformation). If the scalar A is negative (for signed differences for instance), then -log10(-A) should be used instead. I know that this amount at changing a few things when you toggle from linear to logarithmic (sliders, scale etc...), but I think this would be useful for visualization. Scale numbers displayed should use scientific notation (i.e. 1 e-4).

. already in the wish list : would there be a simple way to vizualize the normals attached to a cloud (after calculation or if they are imported) ? You define a subsampling factor (i.e. only 1 vector displayed every 100 point) and a unit vector size with a slider. It seems to me that then drawing a line (no need of an arrow) starting from a point and going to the end of the normal vector would be easy ? Displaying the octree is arguably as difficult ? Because then after, one could this method to map deformation vectors on a cloud.

Cheers

Dimitri

[daniel]

Hi again Dimitri,

- oups, I forgot this color ramp issue, I'll fix it in the next release...
- the latest version has a 'logarithmic color scale' option. It's a very early version, I wait for your comments.
- for the normals, well, it may take more time ;).