UE4 // Book Generator Project

I took a break from C++ programming to focus on something I don't have much experience with; the Unreal Editor. I use Unreal everyday for work but I usually don't open the editor and if I do it's just to test something I've written/modified in C++. I'm not a designer or a gameplay programmer so it's not something I use often.

I decided to come up with a small project that I could easily break down into stages and implement. I like horror games and most horror games tend to have a library in the level. Creating a book and then placing hundreds of them is tedious and a waste of time so I thought a book/library generator would be a nice small and encapsulated project.

After some planning I ended up with 7 stages that started from creating and uv-unwrapping a simple book model to creating a bookshelf blueprint that has books randomly placed when dragged out:

You can drag out this cube and it has 4 different spawn points on it that will randomly spawn, horizontal or vertical stacks of books. They themselves are also randomly spawned.

Stage 1 - Book Creation

I had 4 tasks for this stage; 

1. Create a simple book mesh
2. UV unwrap it
3. Create a texture for it
4. Import it into unreal

I had to re-import it a few times as I kept changing where I wanted the pivot to be and blender's UV map exporter is slightly annoying. My book textures are off by 1 pixel in certain places as Blender can't make up it's mind about hard edges in UV maps.

To create the textures I used a combination of Adobe PhotoShop and an online tool of theirs called Adobe Spark. Spark is fantastic for quickly creating social media graphics as it comes with thousands of templates, free images and fonts. Or well, it's free if you have a CC license (which I do).

The book dimensions are based off a real book off my shelf and the side textures were created by taking a photo of the sides.

Stage 2 - More Textures and a Book Blueprint

This stages tasks:

1. Create 9 more textures for the book
2. Create a way to swap the texture via the editor using a drop down menu
3. When the book is dragged into the editor it will pick a random texture
4. When the book is dragged into the editor it will pick a random scale.

Creating all the textures took me 11 days and by the end I was a bit sick of texturing.

For the next tasks, I became acquaintances with the construction script. Basically, the construction script is run anytime the actor is built and actors are rebuilt on many things:

• Compilation
• Save
• Editor Opening
• Moving/rotating/scaling the actor
• Changing a variable on the actor
• Cooking (building the game for shipping)

It's extremely powerful and useful but also very dangerous. For this I created an enum out of my book covers and then created a random number on construction and used that to determine the book cover. I made these variables public so the cover can be picked manually or set to random by the user in the details panel. I did the same for the scale but only allowed a scale between 0.5 and 1 (1 being full size).

This is pretty comprehensive for a single book but set the foundation for later stages. "Freezing" the settings is a bit complicated as when construction is run, the actor is torn down and rebuilt so any variables on it are set back to default (or whatever they are set to in the details panel). To counteract this I used something called "Random Streams". This way the book is given the exact same seed when FreezeSettings is true, and then when it's rebuilt it will "randomly" choose the exact same random numbers used to set the cover/scale again. When FreezeSettings is false, a new seed is supplied changing the random numbers starting point.

Stage 3 - Horizontal Stacks

The tasks:

1. Create a book actor that is a horizontal stack of books. Allow users to add/remove books to the stack
2. Give the books random scales

This was the hardest stage for me. I started this project on the 10th April and only finished Stage 3 on the 25th July. I had work and other things but I was severely blocked on the stack of books having a random scale applied. I calculate where to place the next book based on the depth of each book added together. This works perfectly, however I was doing this in one place in the construction script:

Yep. I was giving the book a random scale then setting the global bookscale variable with another random scale. I was livid with myself that I made such a stupid mistake. After this progress was much faster and you can bet I triple checked all my blueprint nodes going forward. 

For this you can just drag in instances of BP_HorizontalStack, freeze the settings, unfreeze, set random scales and alt-drag new instances to create stacks of books in seconds.

To increase/decrease the books I set a public slider in the details and then in the construction used a for loop. When the slider changed, it would call to "Add Book", setting the cover/location/scale for the number of books set by the slider. Thanks to the random stream, when frozen, it appeared as though all the settings of the book had been saved when in reality they hadn't.

Stage 4 - Vertical Stacks

The tasks:

1. Create a book actor that is a vertical stack of books. Allow users to add/remove books to the stack.
2. Allow users to align the books left, right and center.
3. Allow random scales.
4. Allow random rotations.
5. "Flip" book so the spine is facing the other way.

The first task didn't take long. I just simple set the rotation of the book to -90 degrees when spawned. This caused all the books to be stacked on top of each other. However they are all very neat with a default right alignment thanks to where the pivot point is. 

To calculate the offsets so they could be aligned differently, I just offset the spawned location on X and Y using 25% of the books length. 

For random rotations I created a random float in the ranges of -90 to 90 degrees on the z angle using a random stream. Again the stream allowed the rotations to be "frozen".

Stage 5 - Stack Extras

The tasks:

1. "Flipped" books so the spines are facing the other way.
2. Rotating some of the books in horizontal stacks

Flipping the books was a bit of head scratcher for me as I realised it was flipping the book at the pivot point so doing a simple rotation wouldn't work. I then remembered that negating the scale of a mesh causes the texture to "flip" without actually changing the scale. Granted the text is backwards if you see it but these books are only, at most, 20cm tall and meant as background decoration so this worked perfectly.

The next task frustrated me for an evening until maths came to my rescue. The next book spawn location is determined by all the book widths added together but how wide is a book when it's rotated slightly? As I drew out the problem on paper I quickly noticed that it created a right-angled triangle where I knew the hypotenuse and theta so I had to use Pythagoras to determine the adjacent (the side of the triangle I was after). I then added that length to my stack length and now it creates randomly rotated books (from angles 0 - 20 degrees) of varying scale:

It's not completely perfect and the end book can end up being rotated as I haven't set anything in place for that but you can just randomise it again. The book rotations are on weighted bools (from streams again, any random numbers use streams) so there's only a 0.05% chance of them being rotated. To rotate them the other way, once the length has been determined, I just move the x location of the book to the end point and negate the angle.

Stage 6 - Bookshelves

The task:

1. Create 2 simple bookshelves to place books on.

For one of the bookshelves I went back to blender and used the exact dimensions of an Ikea Kallax Cube:

I UV-unwrapped it and created material slots so I could just apply a simple wood material from the UE4 starter content.

For the other bookshelf, I placed a load of cubes in the editor, scaled/rotated them and then converted them to a Blueprint:

This isn't as perfect as creating the mesh in blender as the sides are warped but it's good enough and not that noticeable when playing in game.

Stage 7 - Bookshelf Blueprint

The task:

1. Create a bookshelf that when dragged into the editor has books randomly spawn on it.

I ended up doing this task in 40 minutes as I already had all the other blueprints. I simply created a few "spawn points" on the mesh and then called "Add Child Actor Component" in the construction script. These calls were behind random weighted bools so not all spawn points are always used.

And that's it! There are so many more things I want to do and feature creep is rearing it's ugly head but I set out to do specific things; I accomplished that and now it's time to go back to C++ land.

I really enjoyed this task; more so as I got used to blueprint. I remember doing beginner tutorials and wondering how on earth you were supposed to remember all the nodes. The truth it you don't; it's like normal programming only you don't know the language so you search for the appropriate node/google it until you get used to it. Blueprint is super fast for iterating through designs and I rather enjoyed not having to build the editor and open it every time I made a "code" change.

Future tasks do include though:

1. Allowing the blueprints to be cooked out to merged static meshes to reduce draw calls
2. Re-doing everything in C++/Blueprint (I do some heavy maths in blueprint and it hurts my soul)

BlenderGuru's Blender Doughnut Tutorial Review (so good I did it twice!)

If you want to become an indie game developer (or a 3d artist) and you have no money for Maya or 3ds Max then Blender is your saving grace. Thank you Mr Blender creator man for making it free. 

3D modelling is a job in itself but by learning a few shortcuts and basic tools you can create game ready assets in next to no time. In order to do that though you need to learn how to use Blender; enter Andrew Price. I first heard of his tutorial on twitter from one of our environment artists who was doing it during lockdown. It turns out, nearly everyone was making doughnuts during lockdown. I got round to first doing it in October 2020. It took me about 2 weeks but by the end of it I had a nice pink doughnut with sprinkles and a cup of coffee; I was very proud. I then took those skills and quickly modelled a duracell battery I needed for a simple game I was making. 

Andrew takes you through modelling, sculpting, texture painting, lighting, material creation and more with a laid back confidence that's hard to find in tutorials. He doesn't talk to fast, he repeats things, explains when necessary as not to overload you with information and he's also very funny. It kind of feels like a 1-on-1 session with your favourite tutor at uni.

Part 1 focuses on becoming comfortable with the viewport and basic commands like rotate, scale and grab before moving onto sculpting a plain torus into a doughnut shape and creating some icing. Here's a comparison of my attempts:

I was pretty proud of that pink and milky white doughnut back in October but I've definitely improved. I've been doing quite a few material courses and learnt about the importance of roughness, subsurface and other factors like clearcoat. I also spent more time searching for appropriate colours instead of using the colour picker and spent time making sure my lighting was more realistic. Even though there are 3 more levels to go, it feels like I could use that chocolate doughnut as a low-poly stylized game asset.

Level 2 is all about texture painting and adding displacement to a mesh to make it more realistic. I spent a stupid amount of time at the end of this level trying to get the displacement of the donut texture just right. It was one of the major things that bugged me about the 1st donut; it was just too textured. It looks like mid-2000s CGI bread and this is supposed to be a donut. After studying lots of donut pictures and buying a donut myself (that I couldn't even eat because I'm gluten intolerant) I eventually ended up blending two noise textures together to get this slightly bumpy glazed look. Doughnuts are much smoother than you would think given it's a baked treat. It's still not perfect but much more realistic; even if it looks like it should have more texture. I'd like to spend some more time with the pinch and crease sculpting tools though to add some proper detail around the middle as it tends to fold in right where it's been cooking.

I also found that Adobe has a great website called Adobe Colour which allows you to upload an image and create colour palettes from it. You can easily copy the hex values to any program. 

So the third level is the creation of a cup of coffee. I wanted to deviate from the one on the left and used my own reference image of a Bodum glass. They are my favourite glasses; I use them for everything as you don't get any condensation on the outside due to the fact they're double walled. Also, coffee looks beautiful in them as you can see the gradient and the liquid looks like it floating. At first, the glass was just reflecting the inside liquid material however, after messing around with the material settings of the glass I found that setting the alpha to 0.5 allowed you to see through it giving that double walled look. For the foam; instead of using the top part of the liquid mesh and applying a different texture, I duplicated the top face, extruded the edges downwards and then closed them to create a new mesh. This allowed me to deform the foam exactly how I wanted with the sculpting tools without ruining the rest of the liquid (like I did last time, you'll see later). I then stuck a noise texture on top to try and simulate bubbles.

In the first attempt, the liquid was created using volume absorption but I wanted that gradient look. I could've used the nodes in the material editor to procedurally generate it but I opted for UV unwrapping the liquid and then creating a gradient in PhotoShop and texturing it with that.

Level 4 is the final part where Andrew teaches you about depth of field, adding the background and creating an animated scene. I skipped animating it this time, mainly because last time it took my poor gtx 980 six hours to render 20 seconds. I'm incredibly happy with the progress I made this time round. I even added a simple gold plant pot. I didn't make the plant (that was from Quixel) but I did make the tiled print for the plate. I have plates just like these that I bought from Sainsbury's a while ago. I took a photo of them, created a 1k tiled print from it and applied it to the plate.

So there you have it; my donut attempts. I'll probably end up doing this series once more but without Andrew's videos. It's time to take the training wheels off and make a scene myself. 

Blender Beginner Tutorial Series (full playlist)