Meet Blender's 3rd Tree Generator: Grove 3D!

Btw, I am not trying to make a ruckus nor am I interested in sharing or selling 3d models of trees to become rich and famous :wink:

What I dislike is when a developer seemingly blatantly disregards the GPL and Blender’s licensing requirements. What I dislike is when a developer seemingly wants to limit my (legal) freedom to do whatever I like with a generated asset within this original licensing. It is about the law, not about costs. Clarity is key. Otherwise I wouldn’t be bringing it up here.

Perhaps I ought to contact the developer next.


I think contacting the developer is a good idea. It is possible he is just uninformed or he made a mistake. Someone I know emailed him today, no response yet. But two people saying the same thing never hurts.

I think you should contact the developer and I agree with you, you should be able to sale a generated tree especially if you make your own twigs.

The Grove is GPL!

I got hold of the source code, and the file includes the GPL license block.

And regarding whether or not generated trees may be shared or not (the Grove author states they cannot): I discussed this with others, and they agree that when a tree is generated without the developer’s twigs, it will fall outside the GPL license, and the model can be freely shared or commercially sold, because the tree is not based on an existing 3d model and generated from an algorithm from scratch. This means that the generated tree falls outside the GPL (of Blender and the Grove).

But if any of the original twigs or textures are used, the generated tree will include pre-built models which are copyright by the Grove - which means these cannot be shared.

Custom twigs made by the user allows the user to generate trees with leaves and other items and share these as well. But the original textures and twigs from the original developer fall outside the GPL, and if these are used in a generated tree this model cannot be shared, and only images may be rendered.

I suppose the matter is settled with this. Even though the Grove developer asserts that models cannot be shared without their permission, this only holds true for any tree model which uses one of their twigs/textures. Any tree model without twigs or custom-built twigs are completely free to be shared or sold (and should not include any of the original textures!).

# The Grove. Blender Addon to grow true to nature 3D trees.
# Copyright 2014 - 2019, Wybren van Keulen, The Grove
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Before the pitchforks really come out, you do realize the author of Grove works at/for the Blender Institute right??
GNU/GPL is a very tricky subject, and before blasting him into the sun, just ask him personally, and have the guy report here. It’s so easy to derail things like this, and than it tends to start it’s own life damaging more people.


I understand, although I do not understand why The Grove’s website is so vague about the use of the GPL status of the add-on and Blender? And my intention is only to clarify the opaqueness regarding the license of the generated models. The site states tree models cannot be shared. But the add-on is GPL and the generated tree models fall outside GPL when a user generates one with the copyrighted twigs (and textures).

This is confusing, and I therefore did some research myself first.

And this is definitely not meant to derail the thread or “blast him into the Sun”, merely to clarify the status of the generated trees and the add-on itself. The site is SO vague!

The author is hereby invited to comment on this thread. I would be surprised if he hadn’t already noticed this thread. I’ll send him these questions later.

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I understand, but as they say “The road to hell is paved with good intentions” :wink:
The web is often like the ‘whisper game’, where one whispers a story in the first set of ears, and after 15 people the story is completely different.
This is why the author of Grove should be able to tell his side of the GPL story.

we’ll see what happens.

And considering the price, looking at other addons the price is higher, true. Is that a bad thing? Not really, as it looks like a highly specialized tool for a smaller market. (archviz etc.)
Considering the amount of work on this addon, imho it justifies the price. I bought way way more expensive addons in my day for 3D applications.
Just because Blender is free, addons should be automatically free as well?
If one find an addon too expensive, you’re not the target audience :wink:
And on the other hand we should be happy lots of devs are willing to share their hard work for so little money. :wink:

I have no issues at all with the pricing: the Grove is a steal compared to other tree generating software and plugins. I still use XFrog myself, and the reason why I want to know the license status of generated trees is that I am interested in using The Grove’s trees in a game. According to the author I have to contact him and work out a special deal, but the trees generated with The Grove, if not using any twigs or textures other than my own, fall outside the GPL, and are mine to use as I want.

That is the confusion I’d like to see cleared up. XFrog trees are not as nice as the ones from the Grove, so I have been thinking about getting The Grove myself, but the extremely vague website regarding license and the impact of GPL (or not) were contributing factors that lead me to start investigating this.

The author states that trees cannot be shared. But Blender is GPL, and the base trees do not rely on an existing model from which they are generated. This means they fall outside the GPL, and should be mine to do what I want with. Yet the author tells us otherwise.

Then I noticed the twigs and textures are separate installs, which makes them fall outside the GPL of the add-on. Thus, it seemed to me that any tree generated which includes these original models (twigs), would indeed not be legal to share with anyone or use in a game engine without the expressed consent by the author of these twigs and textures, i.e. the The Grove developer.

When the user creates his/her own twigs and textures to be used with The Grove, the end result is entirely theirs to do what they want with. This cannot be taken away by the author, since the plugin is GPL, and the output is generated using an algorithm from ‘nothing’. Thus, the end result falls outside the GPL, and becomes copyright of the user.

And that is what bothers me, because the site is again silent about this, and implies something completely different: tree models generated with The Grove should not be shared according to the site’s wording. But there is no legal basis for this - unless twigs and/or textures downloaded from the site are used in the final tree.

Very, very vague, and ambiguous.

It has nothing to do with the pricing of the add-on. I’ve purchased quite a few Blender Add-ons in the past two years to support the developers. I just want clarity regarding the legal status of the generated models, because it has a large impact on how these assets may be used by the end user.

And I wholeheartedly agree with you that my next step is to contact the developer with my questions. I will do this later today.

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Let’s see what happens. But if he is really strict in his limitations, his sales will surely do take a hit…

It’s a weird situation.

Herbert is pretty much dead on the money as far as the legality of sharing the raw geometry generated by the plugin is concerned. It’s all GPL’ed software running within GPL’ed software, producing GPL’ed results. As long as no one shares the textures, it’s all kosher to distribute.

…but what reason would anyone have to distribute the results produced within The Grove? From what I’ve seen of it, the trees it generates are too high poly to be used for games, so there’s really no concern there. If you’ve edited one of its trees to the point it can be used in a realtime project, you’ve probably done so much work to the base mesh to get things as efficient as possible, it’s barely recognizable as a Grove tree anymore. As long as it’s part of a larger project, as in it has other uses besides being a pack of trees for people to download, then distribute away.

What about giving the trees produced by Grove away? Like generating a pack of aspen trees, slapping your own textures on them, then posting it all up on Gumroad or somewhere for people to grab free of charge? Technically, it’s legal, but it’s cheesy as all get out, considering you’ll be doing it SPECIFICALLY to allow people to get around Grove’s asking price, while still getting to enjoy the end results of the plugin.

Basically, use some common sense, and don’t be cheap. The Grove looks like an all around awesome plugin. If you like their trees, then pay for their trees, and suggest everyone else do so as well. Don’t try to undercut them using their own work against them.

Speaking of games, is there any plan on some functionality to create low poly trees? A lot has to do with the twigs poly count of course, but maybe some further optimization and an automatic way of converting the particles to real geo and joining all in one mesh, so that the trees can be used in a particle system for example.

Is there any plan for this?

So… Any news on this, or do we never know? :wink:

@Herbert123 Did you get a response? My friend emailed The Grove, and sent 2 follow up emails, but he never heard back. Did you have better luck?

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No, I sent an email too, in which I asked him to verify the license status of the generated 3d trees, but no response at all.

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I notified Wybren about your issues.


Thank you!

Time to dust off my old blenderartists account and clear some things up.

Ton’s article was an interesting read, and the discussions below it brought up some interesting points both in favor and against the GPL, it’s not all good. Even Ton himself finds this a complicated matter - to quote Ton: “Disclaimer: I’m not a lawyer and not a license expert. Just sharing how I see this complex matter.”

I am not a license expert as well, and quite frankly it’s the last thing I’m interested in. I have much more interesting things to work on - adding new features and improvements every day. I must say I’m quite overwhelmed with the success of The Grove, and I guess things like these are now part of it.
There’s some interesting points made in this thread, and I will definitely look more deeply into the GPL to find out. But keep in mind that it’s just me working on The Grove, there’s no big evil corporation behind it, just a single 3D / tree addict trying to crack the code of trees and to create the best addon I possibly can.

You are probably right, Blender is GPL, and therefore The Grove (probably) must also be GPL. If this is correct - it’s not even a choice - it’s one of the perks and disadvantages at the same time of creating an addon for Blender. But I decided to release it for Blender anyway because this has been my workhorse software for twenty years now, and I absolutely love it!

So yes, the only thing I ask of you when purchasing The Grove is not to sell tree models - something that is agreed to when purchasing The Grove, and is not part of any license. Again - I hate the idea of a license and would instead much rather count on people’s good intentions. But the question is… can I put this restriction on The Grove’s output, through an agreement that is separate from its license? I don’t know… A valid point, and an interesting thing to find out.

When reading more in depth into the GPL, I’ve come to realize maybe not. It is still complicated, but you (and Ton) are probably right about that - from what I’ve read I cannot impose restrictions on The Grove’s output. So this calls for changes to be made.

But… it may be much more interesting to know why I added this “restriction” in the first place.
Let’s wind back time. I started The Grove around 5 years ago - it joined my passion for 3D, for trees and for coding. I had been creating architectural renders for around 15 years by that time. The need for trees was a personal thing, and I had been pondering about how trees grow for years. Time to scratch my own itch - I decided to experiment, see how I would approach tree growth. That quickly ran out of control and I got hooked.

After the excitement of finally releasing The Grove to the world - straight away a constant stream of mails hit my inbox, asking if it was okay to sell tree libraries grown with The Grove. The shear number of these e-mails discouraged me and it almost felt that there were more people interested in making a buck then there were actual users. These e-mails still hit my inbox every other day. My first replies were in the lines of what @Renzatic said so well. But then after even a seemingly infinite number of individuals, small and even the big companies - 3D software creators, game engines creators, content library creators, and so on and so forth - kept on mailing, I just grew tired of this. I must say however that these individuals and companies have all gracefully refrained from creating tree libraries with The Grove. That shows that they do understand The Grove’s unique position.

You should know that it was a very real option for me to not have released The Grove as an addon in the first place, but instead to use my algorithm to grow a library of tree models. Arguably it could have been a much more lucrative option, the market for pre-grown tree libraries is probably much bigger than that of a Blender addon.

But the way that The Grove works - it is just too much fun to grow trees in such an interactive way! I decided to release The Grove for everyone to play around with, and to have an unlimited alternative to tree libraries. At an attractive price and I even provide free updates to any new version - The Grove is growing quite fast and I want every one of my users to grow the best trees. You can question if this was the right choice, as the amount of support mails rises with every new release ; )

Using The Grove to create and sell libraries of trees is pretty easy, but you’d immediately be a direct competitor to the software. And if everyone who mailed me had grow their own library of trees, The Grove would have died in no time - it would not have become what it is today. I already spent 5 years of my life on creating this algorithm and I’d like to continue improving it every day.

Let’s be honest, it is very possible to model trees by hand. Would it be easy? Most definitely not. But so is spending 5 years on a growth algorithm. Would your trees be as realistic? Probably not. The Grove is doing an enormous amount of work for you.

Thank you for not “blasting me to the sun”. No need to be over dramatic, I’m not taking away anyone’s freedom just by creating something that people seem to like. It seems that the more popular something becomes, the more people want to make it their own, and this is especially the case for software. This is awesome and I see it as a big compliment. But this is also in harsh contrast with content like 3D models and textures, of which the copyright seems to be respected much more. And this is an important point when it comes to The Grove…

The Grove is in quite a unique place, and I’ve come to realize that there’s a good reason why my fellow tree generator developers also have the exact same restriction in place. It’s not just a simple tool like a hammer - a substantial percentage of the work is being done by the algorithm. Yes you are in control, guiding growth, pruning and tweaking the parameters to create very unique trees… But it’s not just a tool - it’s not like modeling from simple elements like polygons from empty space. It’s somewhere in between a model library and a tool, a strange blend indeed…

I can assure you that none of us (creators of tree software) are fond of restrictions, but it is hard to make a living from creating a tool of which the output is a direct competitor to the tool itself… Think about it…

@Herbert123: I appreciate that you’re wanting to use your trees in games, and don’t want to sell them. Yes, you can definitely use the trees you’ve grown in game engines, no need to contact me, that line was put there for completely different reasons and should never have been there. Please go ahead and ignore it, I will remove it shortly.

@Herbert123: I have to correct you on this quote: “He cannot (1) assert copyright over this add-on (because it is GPL…”. This is not true. The copyright for the code DOES reside with me as the author, and apparently this is even required by the GPL.

@RobWu: Although I am close to the Blender Institute, I do not work there. I work on The Grove full time, have so for the past 5 years and hope to continue to do so for a long time to come.

@Renzatic: Very well said, thank you for this - quote: “Don’t try to undercut them using their own work against them.” I couldn’t have said it better.

I will think about all this and in due time I will update the website and readme file in time. I will still ask users not to create tree libraries, but I realize that I will probably have to rephrase some parts. For now, at least ignore the line about game engines.

Have fun growing,

Wybren van Keulen
The Grove


Thank you Wybren for your detailed and well-put answer! It is much appreciated, and clarifies the matter greatly. The GPL can be both a blessing and a curse, depending on the situation.

And thank you for sharing your experience with third parties which only seem to be interested in selling tree libraries. I can imagine how frustrating that must have been.

My only interest is in using tree generators for use in my own work and a 3d adventure game that I am working on. And I would not use the raw generated model: my process is generating a tree, then use sculpting tools to give it some unique identity, and finally optimize it heavily to generate a low poly asset.

For this I have been using my very old copy of XFrog Standalone, but the results aren’t that satisfying or convincing. Trees generated with The Grove look much more useful to me, and it seems to fit my needs much better.

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I have no intention of creating library of trees and selling them. As a freelance artist , I generally provide my 3d model to the client, so I might need to generate trees for a scene and give it to them for rendering,shading,lighting.

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As a purchaser of your WORLD LEADING tool I really appreciate your post.

The only thing I want to reiterate as a user of the Grove is that its secret really is its interactivity with the user and with its environment on top of the outstanding realism. At the end of the day CG is moving towards this level of nuance anyway so there will always be a great reason to use the Grove.

I could certainly see how early on when you had a more limited feature set and the premade trees would meet the industry standard expectation easily how you could have very easily been “washed out” by people selling trees they made in 5 minutes at low cost, however.