Unreal Engine 4 vs PlayCanvas

Blueprints are authoring tools designed for non programmers so designers and other team members can help tweak and prototype. UE4's Blueprint scripts resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish and games a lot faster to prototype.

Epic provides multiple official video tutorials, lots of free example projects and content, an extensive wiki and regular streams showing how to use latest features.

Allows a texture/material artist or VFX artist to create amazing effects from the ground up.

The engine, including full access to source code, is free to use; a 5% royalty is due only when you monetize your game or other interactive off-the-shelf product and your gross revenues from that product exceed $1,000,000 USD.

UE4 gives full access to the C++ source code allowing editing and upgrading anything in the system.

Voxel cone tracing is a similar algorithm to ray tracing, but uses thick rays instead of pixel thin rays to be able vastly decrease the amount of computational power needed.

Unreal Engine 4 is one of the best game engines. It is super easy. It dosent require any use of coding due to Animation Blueprints

This engine exports for a big range of platforms including Linux. The editor can be run on Windows, MacOS, and Linux (Early Access).

Forums have many active and friendly members that are quick to respond and help out. Even staff is very active on forums.

This is ready to make the next AAA game.

Recompiling an entire game to test a small change takes up a lot of time. UE4 quickly compiles in seconds instead of minutes improving iteration time by an order of magnitude.

New feature releases can be commonly expected about once a month.

Almost everything a game developer wants has a deep and sophisticated tool waiting for them in UE4. No external plugins are needed to make powerful materials, FX, terrain, cinematics, gameplay logic, AI, animation graphs, post process effects, lighting etc.

PlayCanvas has an online editor that lets you build scenes and work with other people in your team in real-time. This is all done through the web browser without having to install any additional software.

Assets and content delivery is very different on a web platform comparing to native. So PlayCanvas challenges best practices to allow developers decide how their content is delivered and in what form.

Async Assets download allows developers to load content as the app goes, instead of asking to download all assets in advance risking users to simply navigate away while staring at loading screens.
Formats for 3D models and textures support covers all the popular tools. And the workflow is as simple as dragging and dropping your files right into the Assets Panel. The cloud will do the rest of the hard work optimizing and converting your files into runtime-friendly and compressed data.

Has an advanced WebGL renderer that runs in the browser.

Lightmaps are an efficient way to deliver lighting to your scenes for a long time. But they come with the cost of large textures. PlayCanvas offers a unique solution for a web platform, it renders lightmaps when an app is loading in runtime.

This is faster than downloading MBs of textures. And it's much more convenient: simply switch your light sources to bake, and static models to be lightmapped, and the engine will do the rest.

PlayCanvas has Feed as homepage for registered users, listing Dev Logs of other developers. This allows to socialize with other developers like yourself in a twitter-like environment.
More to that, there is also an active forum, where developers help each other to solve their challenges.

Developers of PlayCanvas itself are always looking forward to chat and help the community with any problems that may arise.

PlayCanvas lets users integrate physics in their game rather easily, using the powerful Bullet Physics Engine (ammo.js). Should also be noted that the physics engine is delivered as an optional library, so by default being disabled it does not add any extra download size to your apps.

Engine is free for projects under 200MB and with no more than 2 people on a team. The free tier has no engine restrictions.

Tools are totally free too. There are no special limiting features behind any paywalls, and free users have all the features as paid users.

There are no royalties associated with publishing your apps and games - you've made them, you own them.

It is free to publish to playcanvas.com as well, just by one click in Editor.

PlayCanvas lets you build games that run in mobile, desktop browsers, and native mobile apps. PlayCanvas can even make games that can run inside mobile social media and instant messenger clients like Twitter and WhatsApp.

The engine itself weighs just under 150Kb, and it's always challenged to stay small. There is no extra weight that has to be carried with your app, just your assets and scripts in a runtime-friendly compressed form.

This allows users to engage with your content in matter of seconds, and even just under a second on a good connection.

PlayCanvas is fully open source and is under active development.

Real-time link between your launched app and the editor allows the developer to preview and play with their scene without needing to refresh the game after every change in the code to see the updated result.