Hello,
I am currently trying to use ShapeWorksStudio to create an SSM from contours (of hand bones).
I have been trying to optimise the parameters for a few days but to no avail. The problem I have is that the particles seem to ‘run around the contour’ leading to bad correspondences. The resulting SSM and PCA scores show the particles then flipping over each other. I’ve tried following the guidelines to parameter optimisation and it doesn’t seem to bring the results any closer to being improved.
The best improvement I had was enabling ‘Procrustes Rotation/Translation’, where the mean is at least relatively circular, but the particles still cross over (would attach screenshots but I can only have one per post as a new user)…
I’ve tried to browse the forum, but as most users seem to be working on 3D meshes, I am unfortunately stuck. Does anybody with more experience on contour-based cases have some advice or pointers?
Hi, is your input data actual contours (point and lines), or is a more like a tube (3d polygons)? I can’t quite tell from your screenshots.
If it’s contours, are you specifying the inputs as contours (e.g. “contour_XXX”)?
Hi,
My data is definitely contours (.vtp files from Python). I did not specify the inputs as contours and that is my bad as I must have missed that from the documentation. I placed all my files now in a subfolder labelled ‘contours’ and the results seemingly have improved. However, during optimization the particles still ‘run around’ the contour leading to ‘crossover of points’ when examining the PCA modes.
If it helps my parameters are as follows.
Num particles: 64
Initial relative weighting: 0,1
Relative weighting: 5
Starting regularization: 500
Ending regularisation: 1
Iterations per split: 1000
Optimization iterations: 1000
Multiscale start: 4
I have tried playing with the (initial) relative weighting and start/end regularization, but I am not 100% sure which parameter can help me stop or limit the ‘running around’ behaviour.
It may not be well documented. If using an Excel file, the column for the shapes needs to start with “contour_”. Otherwise it can’t distinguish between a mesh and contour.
For example:
The name of the column needs to have the prefix contour_. It won’t matter than the files are in a directory with contour in them.
