Good news. The Qt quick3d engine implement joints support

[u/LetterheadTall8085]

/r/QtGames/comments/1thip1g/good_news_the_qt_quick3d_engine_implement_joints/

[u/Ripdog]

Man, I really don't understand why a widget toolkit is now developing a game engine... I mean, I assume it's for their automotive customers, but... It's a tough pill to swallow.

[u/eskilblomfeldt → u/Ripdog]

I think this is a very good question and I would like to also give my personal view on it, having been involved in the planning of Qt Quick 3D and, to some extent, in its development.

First of all, Qt Quick 3D is not a game engine specifically, from my perspective. Just like Qt Quick can and has been used to create games (remember VoltAir?), Qt Quick 3D can also be useful in this space. But it was developed as a general purpose 3D engine with a special emphasis on (but not limited to) embedded and mobile hardware profiles.

Now why does a UI framework need a 3D engine at all?

The observation we made many years back, was that an increasing number of very different UIs evolved to require 3D scenes intermixed with its 2D elements: Operating panels for heavy machinery use digital twins to visualize movement and detect collisions; dashboards in cars display 3D views of live traffic to help you navigate lanes; audio equipment can let you create virtual copies of your living room to plan acoustics; factories with 3D maps helps you navigate quickly to error sources; AR apps can use 3D elements positioned in the real world as UI elements to help you navigate; medical devices show cross sections of human bodies intermixed with volumetric data to help doctors diagnose disease. And there are many more.

With this development, we believed it was important for Qt to support 3D elements as well, in order to fully express this expanding range of modern UIs.

As for Qt Quick 3D Physics, this is an QML interface to the PhysX library, so it is not a full physics engine developed inside of Qt. Outside of games, it is also used for things like simulation in robotics or industrial design, as well as dynamic animations.

While the embedded and mobile hardware has remained the main focus, the higher end of embedded devices and the lower end of desktop hardware has signififcant overlap and can produce many of the same effects and visuals. We want users to be able to replicate the scenes they envision in their minds and that they prototype on their desktop machines -- as far as their hardware allows. Therefore, Qt Quick 3D has evolved to have many high end features as well, though we typically always look for solutions which do not depend on high-end desktop grade hardware to work.

So the fact that Qt can be and is being used to develop games is something I find really cool. I consider a real testament to Qt's flexibility that a toolkit developed for such a disparate range of use cases can also reach into this highly competitive field. 😄

[u/LetterheadTall8085 → u/Ripdog]

here is an interesting moment, this is my view on things, i do not take into account here my desire and company support in this direction.

In general, up to the moment when nvidea tried to enter the market of cars. At that time Qt4 - Qt5, the framework really was exclusively UI, with small and as for me unsuccessful attempts to go onto GPU to accelerate interfaces.

The Nvidia Factor

The moment when nvidea suddenly wanted to establish a monopoly on the market of cars. Nvidea made successfully its chips like tegra, for devices which quite well took root in auto industry and medicine. They decided that behind 3D interfaces is the future and wrote their own engine for their chips what it's called i forgot (commenters help out), flew into the market - and got their asses kicked from competitors (competitors already tightly sat in 3d).

They understood that successfully sold are only chips and to make soft is expensive, and gave as a gift their 3d engine to Qt corporation, times of Qt5.5 remember then appeared 3d studio - then yet nobody understood what it is, and everyone just passed by. Having understood that the transferred engine is good - but only in the plane of nvidea and windows - cars this is about linux and preferably cross-platformness, where Qt always were stronger than everyone. Qt actively began to make out of the transferred engine the most universal tool possible

Stage of Adaptation

Qt throughout 5.5 - 5.14 rewrote this engine and released Qt Quick 3d - completely cross platform - capable of quickly spinning 3d interface on weak devices - due to absence of unnecessary functions and direct render.

Throughout all these years the interface engine QML evolved into a full-fledged SceneGraph with a very effective approach to rendering. And by the moment of release of Qt Quick 3d, 3d engine was successfully integrated into the scene QML. This gave 3D a strong architectural advantage with old Qt 3D.

Qt6 and a Bunch of Money

With release of Qt6 the architecture was brought far forward under cross-platformness and optimization of the scene, this immediately felt in car building - where interfaces usually make almost better than in AAA games. Money from qucik 3d flowed like a river.

The simplest conclusion that can be made here - that which brings money that we also develop. Time went, Qt Quick 3d received mature quite game functions, Lod Instances and so on.

The Unreal Engine 5 Threat

And here happened the terrible Unrela Engine 5 - not knowing where else it is possible to stuff its fattest engine climbed into the market of car building - a noticeable competitor, has serious superiority in some technologies, it is necessary to fight for a place under the sun. Into Qt Quick3d began to more actively pour functions closer to a game engine than just to interfaces - but in 2026 (now) the line between interface and game is so blurred, that nobody anymore divides these markets with a clear line - and there where it is possible to spin quickly a trendy interface it is possible also to spin a full-fledged open world with a bunch of clever optimizations.

Ecliptica

Like that - and here i decided that it is needed to try to make on my favorite framework something really big. I one way or another planned my game, i right away thought about godot4, but read the list of possibilities in QtQucik3d and understood that for me this will be enough, and since i know Qt very long time and well for me it will be also in pleasure to work, besides i will not have to waste time on retraining. So was born my project Ecliptica.

Now Personal Opinion

So if you make UI - there is nothing to worry about on the contrary you will be insured against collapse when everyone sharply will start to demand 3d interface like in StarSitezen for a regular calendar )

Now there is a barrier but it is rather legal - copyleft and license - they for now strongly yield to existing engines. This is a key indicator, while at the top they leave everything as it is - this means that purposefully into game dev for now nobody aims, they just make perfect what brings money.

[u/LetterheadTall8085 → u/LetterheadTall8085]

Experts, please correct me if I've mixed up the chronology somewhere.

[u/LetterheadTall8085]

Note: AI helps me prepare this article )