How to input multiple Metaballs into a Magnet SOP?

Hi there, I’ve been trying to get multiple Metaballs into a Magnet SOP to deform geometry from multiple points. Sadly the magnet SOP does not allow multiple Metaball inputs, so I tried to merge three Metaballs beforehand. But when I merge the metaballs in a Merge SOP they begin to effect eachother and fuse into one another (as metaballs are supposed to do). I wish there were magnet specific metaballs that don’t effect eachother but only the specified geometry. Does anyone here know a way to work this out?

You may be able to use the “Deform Group” and/or “Magnet Group” parameters on Magnet SOP to control which parts of the inputs are being used.
I’m not totally clear on what it is that you’re trying to achieve but you could try using several Magnet SOPs one after another, each with a different metaball.

1 Like

Hi Tekt,

Thanks so much for your reply. I tried using the approach of putting several Magnet SOPS after eachother. But when I visualize the geometry and the magnets together I still see the metaballs fusing together. They do not stay seperated.

How to implement your grouping suggestions still remains a mystery to me. Could you explain how I go about grouping the different elements and then inputting that into the magnet SOP?

I’d upload the sketch but the forum says new users can not upload attachments. I’ll post a download link instead:

The video can be used as input for the “Movie File In” CHOP to have some tracking data for the blob track to work with.

Hope to hear if anyone has thoughts!

If the goal is to apply a magnet based on metaball1, then apply a magnet based on metaball2 to the results of that, etc, Then you don’t need to do anything with groups. You just need 3 magnet operators chained, each using the appropriate metaball.
The group parameters are relevant if you want to either only apply the metaball to part of the first input, or if you only want to use part of the second input as the metaball. So I guess if you wanted to you could merge all 3 metaballs and then use the group parameters to filter it later. But I don’t see a good reason to do that.

It’s worth noting that what TD displays in the viewport for metaballs is not necessarily the same as what is in the underlying data, particularly with metaballs. If you combine several using a Merge SOP, the viewport will show those as merged. But if you middle click on the operator to show the info popup, it will still say that there are “3 points, 3 metaballs” etc. So they are distinct, but when the viewport tries to display them, it displays them as if they were merged, since that’s effectively how they would be used if you used that as the second input on a magnet. But you can still pull those apart using Delete SOP or filter them using the group settings, if you apply a different group to each of the metaballs before merging them.