cura gravity setting?

[neone 40]

Hi all,

Does Cura by any chance has some kind of a gravity setting that is able to more drop an object on to the groundplate?

[nallath 1,120]

The 'old' cura (15.04) has a lay flat function. Not sure if that is what you mean.

[neone 40]

not really I think.

I meant more a virtual gravity setting to test out the virtual model to try and find the best positioning for printing trough simulating gravity.

[Labern 774]

Mesh mixer has a find best orientation setting but it's not gravity related, it's overhang related.

You can load your model in that then orientate the model, save then load in CURA.

I'm not sure if gravity would be the best way to find the best orientation. Detecting overhangs and selecting the best side to print from I think would be the best.

Another consideration can also be strength, where you want the layers a certain way to get maximum strength.

[nallath 1,120]

We're not going to implement gravity any time soon. This would be rather difficult and we have enough quick wins on our list at the moment.

[gr5 2,172]

The printer can lay on it's side or upside-down and printing quality doesn't change. Overhangs are still difficult and lose quality if more than 45 from vertical. Around 80 degrees from vertical they get very bad. Again - gravity doesn't have much to do with it.

There is certainly the "lay flat" feature mentioned above that tries to rotate your part such that most of the surface is touching the build plate. I suspect this is what the other "gravity" feature did.

[NonSequor 1]

I would suspect that using a hill-climbing optimization algorithm to minimize the sum of a potential energy function calculated at each vertex of the model would do the trick. Your potential energy function would only depend on height from build plate so it's not like it's complicated to calculate or anything. How hard it would be to implement the optimization would depend on how easy it is to perform a rotation or translation on the model and peek at the change in the energy function without wasting time rerendering in the UI.

If you ran the algorithm over a variety of different initial orientations of the model (e.g. every combination of 45 degree rotations on the x-z and y-z planes) and take the minimum configuration generated by all of these, I believe it would also tend to find an orientation which would reduce the need for support.

Working out how this would be made available in the UI and tuning the algorithm to make an appropriate trade off between quality of optimization and performance would be harder problems than the calculation itself though.

[gr5 2,172]

Cura does something like this already - it's called "lay flat" I believe.

[nallath 1,120]

Your potential energy function would only depend on height from build plate so it's not like it's complicated to calculate or anything.

 

True, but it would still require a ton of checks. The single check isn't that expensive, but it adds up.

 

How hard it would be to implement the optimization would depend on how easy it is to perform a rotation or translation on the model and peek at the change in the energy.

 

A transformation isn't that expensive, but it would require a few hundred different transformations with thousands of checks for the distance to the place.

 

Working out how this would be made available in the UI and tuning the algorithm to make an appropriate trade off between quality of optimization and performance would be harder problems than the calculation itself though.

 

Yup. I wouldn't even do this in the GUI! In an ideal case we would have an external lib that handles this. This would allow for much faster computation without all the weird hassle of hiding stuff in the GUI.