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Tree supports

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SL1
CW1
SL1S
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Unlike FDM supports, which are usually lattice or grid-like, SLA supports are scaffolding tree-like structures with very thin tips. They’re easy to remove and they leave little to no traces on the printed object’s surface when removed. This also means that an insufficient number of supports can lead to unwanted effects – e.g. heavy objects can detach during the print. Supports go hand in hand with object orientation – by rotating the object to an optimal position, you can minimize the need for supports.

You can get rid of tons of supports if you rotate the object to an optimal position. Teeth on this T-rex head can be printed without supports

Also, keep in mind that removing the supports can leave tiny marks on the surface, so if your object has certain areas that should be completely flawless (an ornament on a piece of jewelry, face of an action figure), try to keep the supports away from them.

PrusaSlicer 2.0 is fully equipped for automatic tree support generation. How does it work?

  1. Select the object that requires supports
  2. Click the SLA support points icon
  3. Choose the support point density and minimal points distance (default values should work fine for a majority of objects)
  4. Click Auto-generate points and wait until the process is finished
  5. Use the Preview mode to inspect whether all “islands” are supported – if not, you can manually adjust the supports.

SLA Support menu in PrusaSlicer

Another thing that you should consider using is the pad. The pad (enabled by default) is a large structure at the base of the print, which serves as the foundation for the supports. While it’s possible to have supports printed directly on the aluminum printing platform, the pad will ensure much better stability.

If you're printing your model solid, it can be quite heavy. Consider Hollowing the model or add more supports, and/or make them thicker, so they can support the object’s weight.

Manual support editing

In some cases, the automatic support generation doesn’t deliver a 100% perfect result – this is normal since imported objects can be infinitely complex. We’re constantly improving our support generation subroutines to prevent these situations from happening. Either way, on certain occasions, supports have to be added manually – this can be done even when there are already auto-generated supports in place.

 

Comparison of automatically generated supports and manually edited supports

Click the Manual Editing button. Previously generated supports will temporarily disappear to give you a better overview of the model. Use the left mouse button to add new support points. You can tweak the support thickness in manual editing mode by using the Head diameter slider, or you can go to Print settings – Supports and modify the following parameters to increase the thickness of supports:

  • Support head front diameter: 0.6 mm
  • Support head penetration: 0.6 mm
  • Support pillar diameter: 1.3 mm

Useful shortcuts

Shift + Left mouse dragAdd multiple points to the selection

CTRL + Left mouse click Add single support point to the selection

ALT + Left mouse clickRemove single support point from the selection

ALT + Left mouse dragRemove multiple points from the selection

CTRL + A Select all points
CTRL + Mouse WheelMove the clipping plane

 

5 comments

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HQPP
Tree support in PrusaSlicer: In this video Jeff will show you how to get tree support in PrusaSlicer for FDM prints. https://www.youtube.com/watch?v=2qNvszl2foU&t=366s
JayFabra
Can you please add tree support for FDM printers? They are much better for printing art models than the grid support. I know there are workarounds, but that's annoying
William H. - Official Prusa

Probably not. Does not make sense for Print speeds etc with FFF printing. Just looks cool.

raew
That's plain wrong, unfortunately. Just one example:
The very same object (a simple post cap) sliced in latest CURA 4.13.1 with tree support takes 7h52m and 125g of filament, while the latest PrusaSlicer 2.4.1 requires 11h16m and 200.5g of filament with its "standard" supports.
Same (default) settings, same printer (MK3), original Prusa printer profiles. Sure there may be differences in detail (e.g. the PrusaSlicer uses 4 top layers as default, where Cura with original Prusa profile uses only 3), but those only make a difference of a few minutes and a gram or two in filament consumption and don't change the overall picture. 
Supports are not the forte of PrusaSlicer (never have been) and you should better acknowledge that and try to improve, rather than dismissing this topic.
 
Dan B
Been trying to figure out for a little while, does Prusa slicer support multiple-sized supports in 1 file?  Eg having "thin" support for delicate detail pieces (sword, arms on a miniature) and "thick" supports for larger parts like the main body/back?  I haven't been able to get it to work, but there's still a lot I have to learn about using the slicer.  Thanks!
Mikolas Zuza

The support head diameter (when manually editing tree supports) can vary. When you click on the model, the current head diameter is used, so you can have tiny connection to the model, thick and extra thick one all at once. However the rest of the support settings can only be changed either globally or for individual objects. You cannot have different support base diameter on the same model at the moment.

DavidUnboxed
Currently, I am using the SL1 profile to generate tree supports, then export it with supports, then import into the MK3S+MMU2S profile so that I can print it with the preferred tree supports. However, this leaves me unable to easily choose to have only the supports or the interface layer be PVA. Please consider adding 'tree supports' to MK3S+MMU22S profile in the slicer - with the option to use soluble supports and the option for soluble interface layer.
97marno
+1 on that
William H. - Official Prusa

I think we will eventually, but there are other considerations with FFF than SLA printing. Even more so when you want to use the MMU2S. We always try to cover most edge-cases as well as general use before releasing a new feature. You can also use another program, like Meshmixer, to generate the tree supports.

ilja
Hi, I have a MK3s, so how can I create supports that start from the object, like in the picture ?
Does it involve meshmixer ?
Giuliano - Official Prusa CS
Hi. This article is about the SL1. However you can also have supports starting from the object on the MK3S, if there are some parts that requires it, like the jaw of the t-rex in the picture.