Highlight — a mod for Minecraft

Highlight — a mod for Minecraft 

• Minecraft version the article was tested and written on: 1.21.10

• Range of supported versions: 1.19.2 – 1.21.10 

• Mod version: 3.9.0

• Dependencies: Fabric API (for Fabric builds) 

Highlight changes the look of the selection outline for some of the vanilla blocks in Minecraft. In the normal game, the contour that appears when you aim at a block is made up of rectangular segments aligned strictly to the X, Y, and Z axes. For blocks with a complex model — slopes, thin elements, or stepped parts — such a contour looks like a rough cube and doesn't follow the actual shape. The mod draws the outline's lines at arbitrary angles, so the selection matches what the eyes see. All changes affect only the client-side render: the hitbox and the response to clicks stay vanilla.

How the outline is rebuilt

The standard selection is a set of rectangular boxes bound to the block's collision. Each box is limited by the axes, so a diagonal line can't be drawn inside it. For cubic blocks — stone, planks, dirt — the outline lies exactly along the surface. More complex models are approximated by steps: small protrusions instead of a smooth slope, a stepped silhouette instead of refined elements.

For such blocks Highlight defines a separate type of contour in which each line is described by two endpoints in three-dimensional space. The contour runs diagonally and follows the model's bevels. The collision geometry is not changed in the process — the game registers clicks, breaking, and interaction by the same rules as without the mod.

new outline on the lectern

List of processed blocks

The reworked outlines are defined in the mod's own internal resources: each block gets its own contour description tied to its identifier. The documentation cites minecraft:lectern as a direct example — once the mod is installed, the lectern's contour runs at a slope that matches the inclined surface of the book stand.

Besides the lectern, the default set covers other vanilla blocks with complex models. If there is no description for a block, the outline stays standard — Highlight doesn't try to automatically rebuild every non-rectangular object in the game.

How to add your own outline

Contour descriptions are stored as ordinary resource files. That's why resource pack authors can override the outline of any block by placing their own description at the same path — the new version will overlay the bundled file. The record structure is simple: a list of lines, each defined by two points in the block's space. Variants for different states are described separately — for example, for the four rotations of the lectern by the cardinal directions.

Conclusion

Highlight closes one visual gap in vanilla: on blocks with a complex model, the selection outline finally follows the real shape instead of stepped geometry. The most noticeable effect is during building and capturing screenshots, where the exact position of an object matters. It suits decorators, builders, and owners of client builds who want a neater look for the game without interfering with the game rules.