Bounding box and force_array

Hello,

I built example-2-contacts/src/main.c to understand the bounding box and force_array parameters.

From the image below, I press on the center of the Morph and the contact info is shown. The blue parameters make sense; the red ones don’t, that is, bounding box and force_array data appear unpopulated.

I would appreciate clarifications. I searched through documentation and couldn’t find an explanation.

Thanks,
Brad

1 Like

Hello Brad,

Thank you for contacting us. You can find more information about the parameters and the contact bitmask on our guide under the Contact Data section: http://guide.sensel.com/api/#contact-data and can be set using the senselSetContactsMask http://guide.sensel.com/sensel_h/index.html#//apple_ref/c/func/senselSetContactsMask.

With regards to the force array, you can check out example-3-forces. You can enable both contacts and forces by passing (FRAME_CONTENT_PRESSURE_MASK | FRAME_CONTENT_CONTACTS_MASK) into senselSetFrameContent http://guide.sensel.com/sensel_h/index.html#//apple_ref/c/func/senselSetFrameContent

Best,
-Alex

Thanks for the assistance. I had been using example-3-forces but decided to dump my code and start again. I hope the image below helps to expose the issue. The only changes I made are in green.

In response to constant pressure from my fingertip, I still only get zeroes for the contact bounding box coordinates:

0.000000,0.000000,0.000000,-0.000000
0.000000,0.000000,0.000000,-0.000000
0.000000,0.000000,0.000000,-0.000000

There was a good stream of force data (“Total Force”) in response to my fingertip press but I then commented that out to make it easier to search for non-zero bounding box coordinates, of which there were none.

Once this contact issue is resolved, then I look forward to finally getting the force array (for each of N contacts) after I change the mask and, of course, the loop logic.

Thanks,
Brad

Hello Brad,

To get contacts and forces with all the existing data plus bounding boxes, you should replace line 78 with these two calls:

senselSetFrameContent(handle, FRAME_CONTENT_PRESSURE_MASK | FRAME_CONTENT_CONTACTS_MASK);
senselSetContactsMask(handle, CONTACT_MASK_ELLIPSE | CONTACT_MASK_BOUNDING_BOX);

This will enable forces, contacts, basic contact data, ellipse contact data, and contact bounding box data.

-Alex

That works nicely! Thanks!

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