Finally a sprite sheet recoloring process that works

I have been searching for a good workflow for testing out different color palettes for existing video game designs.

I have finally found a relatively pain free method of testing different color palettes and applying them to entire games. I will be making a video tutorial about this in the future, but before I get to that, I thought I would already explain the basics of the workflow.

Step 1:

This process will be easier and quicker if you can pack all your game graphics into one large sprite sheet first. For this I used an open source tool called Free Texture Packer. Grab it here:

http://free-tex-packer.com/

Step 2:

Run Free texture Packer and choose “Actions” –> “Load folder” and point it to your sprites folder. From the settings panel on the right, uncheck “Prepend folder name” and “Detect identical”. Then hit “Export”. Your sprite sheet will be saved along with a JSON file that describes the sprite names and locations in the sheet.

Step 3:

Download the open source tool called “Image Palettizer” here:

https://github.com/PureAsbestos/Image-palettizer

Step 4:

Load your sprite sheet into the tool and then load a color palette in the Gimp .gpl palette format. Click apply and let Image Palettizer figure out how to best convert your image to the suggested palette. There are different intermediate color spaces available should you not be happy with the initial results.

Step 5:

Save your color converted sprite sheet and go back to Free Texture Packer. Go to “Tools” –> “Split sheet” and give it the sprite sheet file and the JSON file. It will ask you for a save location and the write your sprites back into their original individual files, even preserving their original names -very nice!

Step 6:

Replace the old files in your game folder with the recolored ones. You have just recolored your entire game based on a color palette! This makes it quick and effortless to try out different palettes for your game designs.

Stay tuned for the video tutorial version!

Basics of Using Cryptomatte in Blender 2.93

In the buttons area (on the right side of the interface), select the “View layer properties” tab.

Under “cryptomatte” turn on “object”, “material” or “asset”. I like “asset” since it let’s me select entire rigs that consist of several parts.

Go to the “compositing” workspace.

Turn on “use nodes”.

Add a viewer node with shift+a –> output –> viewer.

Add the cryptomatte node from Matte –> Cryptomatte.

Connect the image output from the render layers node to the image input of the Cryptomatte node. Connect the “pick” output from the Cryptomatte node to the image input of the viewer node. Render the scene (keyboard shortcut F12).

You should now see different matte colors that identify different assets in your render layer. Use the + button to access the eyedropper tool and select as many assets as you need for the matte you are building.

To see the actual matte, you can plug the “matte” output from the Cryptomatte node to the viewer.

Now you have a matte that you can use in various way when you are compositing. As a simple example, you could color correct the matted area by combining two copies of the input image with the “AlphaOver” node while using the matte as the factor. Then simply drop a color correction node like RGB curves between the bottom image connection.

Hair modeling tips for Blender

I have recently been doing hair renders in Blender and thought I would share some key tips that I have learned along the way:

  1. Use multiple particle systems. If you put all your hair in just one particle system, it becomes really tedious to edit the hair. You’ll end up combing hair that you didn’t mean to etc.
  2. Place the hair manually in hair edit mode (with the add hair brush). So set the initial amount to zero in the particle settings. Comb after every round of hair.
  3. Use simple children instead of interpolated, they are much easier to handle in the edit mode.
  4. To make the interpolated children more fluffy, increase the “radius” value.
  5. Be careful with the Path –> steps value, large values made my Blender crash.
  6. Use the Hair BSDF if you are rendering with Cycles. As of now that won’t work for Eevee so you’ll need to create your own shader for Eevee.
  7. Subdivide the roots of your hair in edit mode, because the hair needs more bend right where it comes out from the head. Also use enough keys when creating the hair strands.

Save bone selection in Blender

Did you know that you can easily save certain bones into a group in Blender so that you can selected those bones quickly when needed? Simply use the bone groups feature to group your bones into different groups that can then be selected from the same bone groups panel. This comes particularly handy when using the pose library: you probably want to create matching bone groups for the poses that you are creating, especially now that the poses are only saved and applied for the bones that you have selected. You can even give different groups of bones different color to be able to visually separate them from each other.

Here’s the process of adding bones to a bone group:

1. Select the bones you want to add to the group (in Pose mode for example)
2. Create a new bone group with the + button
3. Hit the assign -button

Now you can easily selected that set of bones any time from the “select” button.

Blender 2.8 Grease Pencil basics

Getting the started with the new grease pencil tool in Blender 2.8 can be a bit tricky at first. In this post I will simply list some “gotchas” that I bumped into in case it may help others:

Question 1:

Why can’t I create a fill color for my object with the fill-tool?
I’m clicking inside a closed stroke, but the stroke seems to be getting thicker instead of a fill appearing.

Answer:

You probably need to set the fill opacity alpha to 1. it’s zero for materials by default which makes the fill transparent.

Question 2:

How can I tween or interpolate between grease pencil shapes?

Answer:

The basic tween workflow can be tested like this:
-Draw a shape
-Duplicate the first keyframe on the dopesheet timeline (shift + d) and move it further in time
-Go to this second keyframe and enter the sculpt mode
-Change the shape of the stroke by sculpting
-Go between these two keyframes and from the “interpolate” menu on the top choose “sequence” to have Blender automatically create the in-betweens

Question 3:

Why does the brush size and strength change from what I set it to be in the top bar when I try to sculpt my strokes with grab tool in sculpt mode?

Answer:

Still working on the answer for this one! 🙂

Question 4:

What’s the difference between “Draw block”, “Draw ink”, “Draw Marker” “Draw Noise”, “Draw Pen” and “Draw Pencil”?

Answer:

Try them and you will see they all produce a different kind of stroke. The Draw Ink -brush doesn’t seem to do ink-like angles when painting with a mouse, but using a pressure sensitive tablet and pen helped.

Question 5:

How do I create new grease pencil layers or collections in 2.8?

Answer:

You can add new layers to grease pencil by selecting the little pen icon in the properties area (one tab before the materials tab) and creating layers there.

Question 6:

Where does the white background come from when using the new 2d-animation project preset?

Answer:

N-panel –> “grease pencil paper”

Question 7:

How do I select the grease pencil material before starting drawing?

Answer:

The option to select the material beneath the brush selection is grayed out for some reason. But here’s how you can choose your material colors before drawing anything: go to the materials tab and create a new material slot there. Add a new material to the material slot and change the settings to what you want. If you now draw with the grease pencil, new strokes should get this new material.

Question 8:

How can I assign different grease pencil layers different materials? At the moment changing the material seems to affect all grease pencil layers. I would like my fill layer to have a different material from my line art layer.

Answer:

Take the grease pencil object to edit mode, add a second material slot, add a new material to it, select the lines you want to affect (hiding the eye of the other layer can help), and click assign.

Question 9:

How can I change the origin of the grease pencil object?

Answer:

Place the 3D cursor where you want the new origin and go to object –> set origin –> origin to 3D cursor. Unfortunately this will also move move the location of the object. Now there is a very strange workaround at the moment (probably due to a bug), but you can set the position back to the original position after changing the origin by doing the following: object –> snap –> selection to cursor. And after that undo once and it seems to return to it’s proper location.

Question 10:

How can I quickly switch between draw mode and sculpt mode with a keyboard shortcut?

Answer:

I’m not sure if there is a default shortcut yet, but you can easily assign your own shortcut by opening the menu item, right clicking on it and selecting “assign shortcut”. The fastest and most future proof way might be to open up the pie menu with ctrl+tab and switching between the modes from there.

Basic workflow suggestion for 2.8 Grease pencil:
-Add a new empty grease pencil object in object mode (shift+a keyboard shortcut). This step is needed to be able to activate the draw mode in the next step.
-Switch from object mode to draw mode
-Select your pencil/brush type from the left side tool panel
-Modify your brush settings from the “tool settings” panel in the right side property buttons -area. You might want to try the turn on the “active smooth” for example to get an interesting, smooth and accurate drawing experience even with just the computer mouse.
-Sculpt your strokes in the sculpt mode. You can for example add width variations to the stroke with the width tool.
-Go to the materials tab and change stroke color and add a fill (change fill opacity to 1 first)

That’s it for now, I will append this article with more questions and answers as I continue studying the tool.

Best practices for creating new scenes in Blender

The possibility of creating new scenes comes really handy in Blender: instead of creating multiple .blend files and keeping track of them, you can have a single .blend file with various different scenes instead. You can create new scenes from the “Scene” menu at the top of the interface by clicking on the little + button. When you do so, you will be presented with five different options:
“New”
“Copy settings”
“Link objects”
“Link object data” and
“Full copy”

In this article we will explain the differences between those options.

NEW
Selecting “New” will create a completely empty scene with all the settings set to default. This is rarely what we want, since typically we want to use at least some common settings between the various scenes and usually we want to share things like meshes and armatures as well.

COPY SETTINGS
Selecting “Copy settings” will create a completely empty scene, but with similar settings than in the previous one. These settings can be things like the “render” settings and “scene” settings.

LINK OBJECTS
Selecting “Link objects” will create a scene with all the same objects and every aspect of them is linked together: if you rotate an object in the first scene, it will also rotate in the second scene. While one can imagine situations in which this is useful, it doesn’t offer us the flexibility of creating different animations in different scenes for the same objects. It can however be a handy starting point: perhaps you want some aspects of your scene, like the surroundings for example, to be fully linked so that if you reshape the landscape in scene 1 it will automatically also change in scene 2. You could combine that behavior with making some objects independent of each other with the “make single user” command.

Link objects can also be used as a clever way of alternating between different selections, since selected objects are scene-independent. So you could have some objects selected in scene 1 and other objects selected in scene 2 and then switch between those scenes simply to decide which set of selected objects you currently need.

LINK OBJECT DATA
Selecting “Link object data” will create a scene with all the same objects and settings. The objects will share the same meshes, vertex groups, materials etc but they can still be independently manipulated in object mode (like translated, rotated and scaled for example). Editing the mesh in edit mode will edit the mesh all the scenes. Creating a new animation in one scene will not repeat that animation in the other scene. However, any animations before creating the new scene will share the same action and if you edit such an animation in one scene, it will also change it in the other. If that’s not what you want, you need to make the action “single user” by selecting “object” –> “make single user” –> “object animation”. Now those two objects can be animated individually. This “link object data” option is probably the one to go for as it offers a good balance between freedom and connection.

FULL COPY
Selecting “Full copy” will create a scene with all the same objects and settings but everything will be an independent copy. So changing things in one scene will in no way affect the other. This is very stress free and gives you the ultimate freedom, but you also loose all connectivity and can end you up with a very bloated project file, because everything is always duplicated. So for example the same material can end up having tens or even hundreds of copies so changing the material can get tedious.