Line Extender

Line Extender adds two purpose-built construction tools for extending connected block lines quickly and precisely. Use a normal right-click to move an entire line forward by one block, or hold Shift to fill every valid space up to a boundary.

The mod is designed for repetitive structural work such as frames, walls, roads, beams, outlines, and large builds where placing every block by hand becomes tedious.

Features

- Extends a connected line using the exact block state you clicked.
- Normal right-click extends the whole detected line by one block layer.
- Shift + right-click fills the complete valid distance to the boundary.
- Live world preview shows exactly where blocks will be placed.
- Separate tools for vertical and horizontal construction planes.
- Closed or hollow outlines can be filled from the inside without spilling outside the frame.
- Any non-air block can act as a boundary; no special boundary block is required.
- Survival mode consumes matching blocks from your inventory.
- Creative mode places blocks without consuming materials.
- Each tool has 256 durability and loses one durability per successful use.
- Source detection stays inside the active construction plane, preventing nearby off-plane blocks from being included accidentally.

How to Use

1. Hold the appropriate Line Extender tool.
2. Aim at a block in the line you want to extend.
3. Right-click the horizontal face pointing in the desired extension direction.
4. Check the colored placement preview.
5. Use a normal right-click for one layer, or hold Shift while right-clicking to extend all the way to the boundary.

The placed blocks always match the clicked source block. In Survival mode, you must carry enough of that block in your inventory.

The Two Tools

 Vertical Line Extender

The blue tool works in a vertical construction plane. While extending forward, non-air blocks directly to the left or right act as boundaries.

This is useful for upright frames, walls, vertical outlines, and similar structures.

Horizontal Line Extender

The orange tool works in a horizontal construction plane. While extending forward, non-air blocks directly above or below act as boundaries.

This is useful for floors, roads, ceilings, horizontal frames, and ground layouts.

Hollow Frames and Enclosed Areas

When the connected source blocks form a closed hollow outline, use the tool from an inward-facing side of the frame. The mod detects the enclosed air region and restricts placement to that interior.

- Normal right-click fills the next inner layer.
- Shift + right-click fills the valid enclosed area to the boundary.
- Blocks outside the detected outline are left untouched.

Placement Preview

While holding either tool and aiming at a usable source block, a colored outline displays the planned placement area:

- Blue preview: Vertical Line Extender
- Orange preview: Horizontal Line Extender

In Survival mode, the preview is limited to the number of matching blocks currently available in your inventory.

Crafting

Vertical Line Extender

Place Shears in the center of a crafting table and Iron Ingots directly above, below, left, and right.

Horizontal Line Extender

Place Shears in the center of a crafting table and Copper Ingots directly above, below, left, and right.

Notes and Limitations

- The extension direction must be horizontal; click a side face rather than the top or bottom face.
- The source must be a placeable block with an inventory item.
- Blocks containing block entities are not supported as source blocks.
- Placement stops before the detected boundary and never replaces existing non-air blocks.
- The player must have permission to build at the clicked source block.