Troubleshooting & Known Issues

This page documents current limitations, common problems, and workarounds for The Violence Tool (v1.0).

If you are stuck in the middle of a workflow, check the Inline Tips in the Use Cases first (find the workflow you’re in, and check where the problem is). If you have a describable problem, you can try finding your symptom below.

Drawing & Strokes

Nothing happens when I click a layer button.

  • Cause: No Grease Pencil object is selected, or you are not in Draw Mode.

Possible Fixes:

  • Select the Grease Pencil object in the Outliner (top right) if you can’t click it in the viewport.

  • Ensure you are in Draw Mode (Ctrl+Tab → Draw), not Object Mode.

  • If the object is new/empty, draw a test stroke first to make it selectable.

My strokes are invisible.

  • Cause: The “Black Stroke” material slot is missing, unassigned, or the brush is set to “Fill”.

Fix:

  1. Go to Material Properties (Red Ball icon).

  2. Ensure a material named “Black Stroke” exists in a slot.

  3. Click the material, ensure Stroke is checked (not Fill), and color is Black.

  4. In the Tool tab (N-panel), ensure the brush is set to Ink Pen.

The fill tool says “Unable to Fill”.

  • Cause: The area is not a closed loop, or you are trying to fill a “donut” (shape with a hole).

Fixes:

  • Zoom in and check for tiny gaps in your lines. Close them in Edit Mode.

  • For Holes (Donuts): Grease Pencil cannot fill a hole directly.

    1. Fill the outer shape with your main color.

    2. Create a new material with the background color (e.g., White).

    3. Use the Fill tool with the new material to “punch out” the hole.

Strokes look soft, faded, or blurry.

  • Cause: The brush is not set to Ink Pen with Hardness 1.0.

Fix:

  1. Press N to open the sidebar.

  2. Go to the Tool tab.

  3. Under Stroke, change the pencil type to Ink Pen.

  4. Set Hardness to 1.0.

I can’t draw on a new Grease Pencil object.

  • Cause: Newly created GP objects may have default layers that don’t work with the tool.

Fix:

  1. Delete all existing layers on the GP object.

  2. Create a new layer manually (click the + button in the Grease Pencil properties).

  3. Ensure the new layer is active (highlighted green).

  4. Ensure you are in Draw Mode (Ctrl+Tab → Draw).

My strokes are drawing on the wrong layer.

  • Cause: The layer may be locked, hidden, or the tool didn’t switch properly.

Fix:

  1. Check the Outliner to ensure the target layer is unlocked and visible.

  2. Click the layer button again to force a re-switch.

If the problem persists, manually select the correct layer in the Grease Pencil properties panel (green icon).

Materials & Colors

Materials look wrong after switching layers.

  • Cause: The material slot may not be assigned correctly to the active layer.

Fix:

  • Check the Material Properties panel to ensure the correct material is assigned to the active slot.

Note

Remember: strokes are assigned to material slots, not specific materials.

I can’t make a “donut fill” (a fill with a hole inside it).

  • Cause: Blender’s Grease Pencil fill system does not support fills with invisible holes.

  • Fix: Create a separate cutout material (same color as the background) and use it to “punch out” the area you want to be empty. This is a limitation of the Grease Pencil system, not the tool.

Changing a color changes it on EVERY frame.

  • Cause: You are editing a Shared Material slot. Material slots are shared across all keyframes by default.

  • Fix:

    1. Click the “New” button (shield icon or arrow next to the material name) to create a Unique Copy.

    2. Change the color of the unique copy.

    3. This ensures only the current frame (or selected strokes) are affected.

Be sure to name this layer something clear.

Warning

You’ll probably not have to do this on Fred’s projects, let him know if you run into a material problem.

Performance & File Size

My .blend file is huge (>100MB) or Blender is slow.

  • Cause: Grease Pencil strokes can contain an excessive number of vertices (vertex bloat), especially with pressure sensitivity.

  • Fix: Use the Adaptive Simplify tool:

    1. Select all strokes (or enable Multi-Frame Editing to select across frames).

    2. Press F3 and search for “Adaptive”.

    3. Set the threshold (start with 0.001 and adjust).

    4. This reduces vertex count with minimal visual impact.

Blender is running slowly with the tool active.

  • Cause: Too many visible layers, complex materials, or active modifiers.

  • Fix:

    • Use Fade Inactive Layers (Ctrl + F) to reduce visual clutter.

    • Hide layers you aren’t actively editing.

    • Switch to Solid view (Z → Solid) while drawing, and only use Rendered view for previewing.

My art looks distorted.

  • Cause: Strokes were drawn with depth (projected from the camera to the origin point).

  • Fix: Flatten the art using Reproject Strokes:

    1. Go to Edit Mode (Tab).

    2. Select all strokes (A).

    3. Press F3 and search for “Reproject Strokes”.

    4. Choose “Project from View”.

    5. This flattens the drawing to the current camera view while preserving its appearance.

Dope Sheet & Keyframes

I can’t see my keyframes in the Dope Sheet.

  • Cause: The Dope Sheet is not set to Grease Pencil mode.

Fix:

  1. Open the Dope Sheet (change a window to Dope Sheet).

  2. Click the Dope Sheet dropdown menu (top left of the Dope Sheet window).

  3. Change it from “Dope Sheet” to Grease Pencil.

  4. Open the Summary arrow to see all layers.

Keyframes disappeared after I deleted strokes.

  • Cause: If you delete all strokes on a layer, the keyframe for that layer may also disappear.

Fix: Insert a new blank keyframe (I → Insert Blank Keyframe → All Layers) to recreate the keyframe.

The “Add Keyframes” button doesn’t work.

  • Cause: This may be related to the Operator #15 issue (inactive operator).

Fix: Use Blender’s standard keyframe shortcuts instead:

  1. Move to the desired frame on the timeline.

  2. Press I and choose Duplicate Active Keyframe → All Layers.

  3. Edit the new frame.

My keyframes aren’t playing back.

  • Cause: The playback range may be incorrect, or the Dope Sheet may have “hold” checkboxes enabled.

Fix:

  1. Check the Timeline start/end frames.

  2. In the Dope Sheet, ensure the hold checkboxes (next to each layer) are not freezing the frame.

Installation & Setup

The “Fred” tab doesn’t appear in the sidebar.

  • Cause: The script wasn’t run, or failed silently.

Fix:

  1. Make sure you clicked the Play button in the Text Editor (Method 1) or enabled the add-on in Preferences (Method 2).

  2. Press N to open the sidebar and look for the “Fred” tab.

If it still doesn’t appear, check the Blender System Console (Window → Toggle System Console) for error messages.

Errors appear in the console after running the script.

  • Cause: Blender version incompatibility.

Fix: Ensure you are using Blender 4.1.1. Other versions may have incompatible API changes.

Warning

The tool uses Grease Pencil APIs introduced in Blender 4.1+.

The script overwrites my custom changes.

  • Cause: Running the script re-executes the entire file from scratch.

Fix: Always save a backup of your modified script before running it.

General Blender Issues

These are common Blender issues that you might encounter.

I can’t select the Grease Pencil object in the viewport.

  • Cause: Empty GP objects (no strokes drawn) are very hard to click.

Fix: Select the object by name in the Outliner (top right), or click near the orange origin dot.

Known Issues for v1.0

The following are known limitations in the current version. These are being addressed in v2.0.

Operator #15 (“New/Clear Mouth Frames”)

  • Not functional, not showing in panel.

Workaround: Use standard Blender keyframe shortcuts (I → Duplicate Active Keyframe).

Operator #30 (“Hide & Exit”)

  • Not functional, not showing in panel.

Workaround: Manually hide layers in the Outliner instead.

Limited Undo

  • Some tool actions cannot be undone with Ctrl+Z.

Workaround: Save frequently before using tool operations.

No Error Feedback

  • Clicking buttons without a GP object selected does nothing — no warning or message.

Workaround: Always select a Grease Pencil object first.

Hidden layers can’t be edited

  • Layers hidden in the Outliner are skipped by the tool.

Workaround: Make layers visible before attempting to edit them.

Brush size may not update

  • Brush size may not match expected layer defaults after switching.

Workaround: Check the Toolbar (left side of 3D Viewport) and adjust manually.

Reporting New Issues

If you encounter a problem not listed here:

  1. Check the Blender System Console (Window → Toggle System Console) for error messages.

  2. Note the exact steps that led to the issue.

  3. Report the issue on the project’s GitHub Issues page with:

    • Blender version

    • Description of the problem

    • Steps to reproduce

    • Any error messages from the console

Future Improvements

The following issues are (theoretically) planned to be resolved in future versions:

  • v2.0: Integrated undo support, user error messages, known issues fixes, developer API.

  • v3.0: Character switching, materials setup.