Cura Tree supports are generated within the Cura software to help support areas of a 3D print which wouldn’t successfully print otherwise.
The difference between tree supports and standard supports is that the standard generates directly below the supported area only.
The tree supports “grow” around the supported area, much like the branches of a tree, and provide more specifically directed support to that area.
The supports start out thicker at the bottom and then get thinner as they rise and branch out to connect with the particular point of the 3D print.
This, therefore, gives them the resemblance of a tree, hence the name.
As you may already know, Cura is a popular 3D slicing program that allows you to prepare and provide settings for the object you wish to 3D print.
Within the program, you can set parameters for a multitude of different print settings to ensure the best outcome for your print.
There are other choices for slicing software, but Cura is the popular choice among users and provides good coverage when it comes to tree support.
There are many factors which go into creating the best tree support for your model.
What are Tree Supports and Why are They Important?
As we’ve mentioned, tree supports provide extra stability to your model during the 3D printing process.
Now, you may be thinking that you’re already adding supports to your model, so what’s the benefit of tree supports?
Well, the normal supports you might add to a model will only support vertically and only at the point nearest to the build plate. This is fine for less complex models where the part needing support is a standard shape.
However, tree supports will give stability to more complex or delicate parts of your model which might need supporting throughout their structure.
For example, you may want to 3D print a model of a person or character from fiction.
If that model is just the figure standing with their arms by their sides, then it’s unlikely you’ll need supports at all.
If you then move their arms outward or have them pointing, then the arms are going to need supporting.
Standard supports should work fine in this case if there is nothing between the arm and the build plate.
However, if the design becomes more complex, and you have the figure holding a sword for instance, or in a moving or fighting pose, then the need for tree supports may be apparent.
The tree support will not only support the lowest part of the extended piece, but will wrap around the sword to ensure it is supported correctly.
In effect, you’re creating a higher level of the build plate, but in the branches of the tree.
A good comparison here would be if you were to build a tree house in your garden. The floor of the house will be built around the trunk of the tree, and it would be the tree providing support rather than anything touching the ground below.
So, how do we go about enabling tree supports in Cura?
Let’s take a closer look at this now and see what’s needed.
How To Generate Tree Supports in Cura
When opening Cura for the first time, you’re presented with a fairly basic looking User Interface (UI) which is a simple 3D view of your printer’s build area.
We’ll assume for the purposes of this guide that you have some basic experience of using Cura, so the UI will be familiar to you.
If you need to know more about Cura in general, then it would be useful to familiarize yourself with the basic controls first.
Once you have Cura open and running, go to Settings on the top bar and select Configure Setting Visibility from the drop-down.
This will then open up another window with a whole list of available settings you can add to your workspace view.
In case you’ve already defined what settings you want to have there, you can go directly to the toolbar on the right side and find Support Setting.
We’re just going to be focussing on the tree support settings, so scroll down until you find those.
You’ll see that there are several options, so let’s look at what each of these means:
- Branch Angle: The angle of the branch. A lower angle will make them more vertical and stable, but a higher angle will give more reach to the branch.
- Branch Distance: This is the distance between branches at the point they touch the model. Making the branches closer to each other will give better overhang support, but will make removal more difficult.
- Branch Diameter: This is the diameter of the branch at its thinnest point, closest to the model. The thickness will increase towards the base in scale with this setting.
- Branch Diameter Angle: This follows on from the previous setting and dictates the gradient at which the thickness increases. An angle of 0° will give uniform thickness over the length of the branch. Adding a small angle will increase stability of the tree support.
- Collision Resolution: This will calculate where branches are likely to collide with the model. Setting this lower will give more accurate trees and less failure but will increase slicing time.
You’ll notice that there is a multitude of different support settings in general, but don’t worry too much about those at this stage.
You will however need to look at the Material Settings and add those. To be able to actually adjust the settings, you need to “tick” the select box next to each one in the list.
This will then add the availability of that setting to the side menu on the Cura UI.
If you open up this side menu, you will need to select the Custom Settings option from the drop-down menu. This will show all the settings you’ve previously ticked and made visible.
Scroll down to Supports and then select Generate Supports which will open up the rest of your available settings.
As we’re looking at Tree Supports, change the Support Structure setting to read Trees; this will then bring up the settings we’ve looked at above.
The default settings for these in Cura are:
- Branch Angle: 40.0°
- Branch Distance: 1.0 mm
- Branch Diameter: 2.0 mm
- Branch Diameter Angle: 5.0°
- Collision Resolution: 0.2 mm
These settings will work fine as a starting point and are the average user-defined figures that have shown to work well.
You could then leave these settings as they are, and your tree supports will work fine for your model.
As with most things in 3D printing, trial and error play a big part in determining the optimum settings for Cura tree supports.
The tips given in the previous bullet point are valid in this case and should therefore be used as a good guide to adjust the settings as required.
As we alluded to earlier, selecting the right material and infill settings are also a crucial part of achieving a good support.
However, tree supports are generally hollow, as adding any infill pattern would in effect make them completely solid.
This has both good and bad points. It will of course use less filament and make them easier to remove but will make the support slightly weaker.
Let’s now take a closer look at some of those settings and see what advantages can be gained by changing them.
Advanced Tips For Using Cura Tree Supports
We discussed how the default settings for tree supports are a fairly good benchmark to go by.
However, if you want to get the best out of the settings Cura has to offer, then you may need to consider tweaking these to suit your particular model.
Previously, we gave an example of a printed figure as being something that might need tree supports. Now, let’s now take a look at a specific model and what tree support settings might work best with that.
I used this model of a “Chubby Thor” which I found on Thingiverse.
It was a fairly simple design but highlighted the potential benefit of having tree supports for the arm and Thor’s Hammer.
Example 1: Default Tree Support Settings
As you can see from the first slicing in the images, I used the default tree support settings in Cura.
This provided adequate tree supports for this model, which can be seen shaded in black in the images.
You’ll notice how the supports are curved around the model instead of just vertically as with standard supports. This does give quite an interesting view of the model and makes it feel more sculpted in my opinion.
The slice took around 12 minutes to complete, so a fair bit longer than the standard 1–2 minutes.
The print time for the model on a Creality Ender 3 Pro is also long at over 32 hours with an estimated material usage of 148g/49.77 m.
But that’s to be expected with the added supports and the size of the model. Sure, you could scale the model down to decrease print time and material usage.
These images show different angles of the same as viewed in Cura and after the slicing has taken place.
You can see the tree supports in black compared to the magenta of the model. It shows clearly how they have wrapped themselves around the model to provide optimum support.
Example 2: Customized Tree Support Settings
In this second example, using the same model, I adjusted the settings slightly for each parameter as shown in the images.
So, the following were the new settings:
- Branch Angle: 60.0°
- Branch Distance: 2.0 mm
- Branch Diameter: 1.0 mm
- Branch Diameter Angle: 3.0°
- Collision Resolution: 0.2 mm
These were only slight changes in each case, and I left the Collision Resolution as it was.
The results weren’t much different, and the slicing time was still around 12 minutes.
However, from the images, you should be able to see the change in the shape of the tree supports from the default settings. They have now gained a further reach in respect of the arm and the hammer.
The print time is now estimated at just over 28 hours and material usage is 130g/43.66 m.
This shows that any change in the tree support parameters can be of benefit to the quality of your print, the print time, and the material used.
These images also show a slight change in the formation of the tree supports, as mentioned.
Troubleshooting Common Issues
As is the case with most things, problems occur when using tree supports in Cura.
However, having looked online, there don’t actually seem to be that many anymore since regular updates and beta testing are fairly good with Cura.
The most common problem I’ve heard about from the community:
Unnecessary Generated Supports
This is something Cura does not excel against other competitors like Prusa: Manual Support function.
There is basically only the automated Support Generator or the Blocker, which does solve the issue in most cases.
The Blocker defines the areas where no supports are needed. You can find the function at the bottom of the left toolbar.
Another common issue when generating tree supports in Cura is that the supports are not fully generated and added to the model.
To solve this, find the Support Wall Line Count and check the value. By default, it should be set to 1, which is fine.
This setting is related to the number of walls around the infill. This will generate a stronger infill structure of the added support.
It is not advisable to increase this number if not necessary, as this will boost the material usage and printing time – unnecessary.
Do tree supports use less filament?
Yes and no. Depends on the circumstances. Tree support will generally use less filament than standard support, as it has less height to cover and a smaller base.
However, you may need to have many branches to your tree which can use more filament, so the saving of materials may be minimal.
Should I enable combing in Cura?
Combing avoids the need for retraction of the nozzle from the model as often, and therefore prevents issues such as stringing and overuse of filament.
Enabling combing in Cura will have an effect on your tree supports, as your printer’s nozzle may then be limited as to where it can go.
Using tree supports isn’t necessary for the majority of models that you may slice/print.
But they can definitely be of benefit to more complex models or those with a pronounced overhang.
There are also the added benefits of less printing time and material usage, which is always a bonus when it comes to 3D printing.
Getting the settings right can be a case of trial and error, but with experience, you should be able to get the results you need.