When an item maker creates an item one of the things they build into it is the placement parameters. Sometimes they leave the placement parameters defaulted or use a non-standard grid. In those cases it might aid your mapping to be able to place that item along the same grid as the game's default blocks snap to.

Step 0 - Open the Editor Helpers Window

If you do not already have the Editor Helpers window open then follow the directions here to open the window.

Step 1 - Override the Item Grid

Scroll down to the Custom Item Placement interface (in the "Build" section) and check the box next to "Apply Grid to Items" to allow the plugin to override the item's built-in grid.

Step 2 - Set the Grid to Game's Standard Size

In the "Horizontal Grid" and "Vertical Grid" input the following:

Horizontal Grid	32
Vertical Grid	8

The game's internal units system measures one block on the grid as being 32 meters in length/width and 8 meters in height.

Depending on where the creator placed the item's pivot point the item may be snapping to an offset of the grid instead of aligning directly with the Nadeo blocks. If this occurs then divide the "Horizontal Grid" setting by 2 until you reach the desired results. So 32 -> 16 -> 8 -> 4 -> etc.

Related

See the reference for Custom Item Placement to read more about overriding the item grid and other properties.