Legacy:Snap To Grid

From Unreal Wiki, The Unreal Engine Documentation Site
Jump to navigation Jump to search


This subject is basically intended for novices, since most l33t level designers always enable the Snap to Grid feature of the UnrealEditor. From experience mappers have noticed that UnrealEd operates much better when the Snap to Grid feature is on.

  • Geometric brushes line up together perfectly
  • Clean joins look professional during gameplay
  • the 2D view is simpler & easier to understand
  • reduced chance of BSP holes
  • can result in a smaller filesize.
  • eliminates having to make alterations after every level rebuild (I'm not sure what this means, but obviously means something – Tarquin )
  • Allows Unreal to calculate occlusion factors faster and more efficiently.
  • reduces occlusion time.

For snap to grid to do all of the above, it's important to do the following:

  • Make the dimensions brushes multiples of the grid size. Eg 32, 64, 96, 128 etc.
  • Never use the brush scaling tool to resize brushes. In UnrealEd 2 it's buggy and will increase your brush's dimensions by grid fractions. Use vertex editing mode instead.

Most importantly, when your brushes are aligned to the grid, that horror, BSP Holes are relatively infrequent, or totally absent from the map.

Legacy interface.consolebar.gif

Grid snap is toggled with icon #4 in UnrealEd's console bar. It's green if active, grey is inactive. Click it to toggle between the two.

Rotation Snap Adjustment

In the UnrealEd Advanced Options (and also UT200.ini under [UnrealEd.UnrealEdEngine]) are the snap settings.

there's a line wich says "RotGridSize=(Pitch=1024,Yaw=1024,Roll=1024)"

By using a little math, you can change this setting to your needs:

UT works with a space from 0-65535 (65536 units)

65536=360 degrees

65536/64=1024 –> that means that every snap is the 64th of a complete circle wich is equal to 1024 unreal-units

In my case i needed a snap to every 48th (7.5 degrees) of a circle (65536/48=1365.3125 unreal-units)

Too bad that snapping to values with decimal places doesn't work lowering it to 1365 will surely cause a lot of holes in your level but you can use these values safely:

  • 32768=180 degrees
  • 16384=90 degrees
  • 8192=45 degrees
  • 4096=22.5 degrees
  • ...

Snap to grid with already distorted brushes

You have built something and now it is between the grid? You imported something which is between the grid? And now you have BSP-Holes?!

Don't rebuild everything!

  • Activate your grid.
  • Select the grid size you need.
  • Select Vertex Editing Mode.
  • Select your vertex. Not your vertices, just one, even if they are stacked along an axis of the same brush!
  • Right-Click on it.
  • Done.

Other things to cover:

  • pivot point,
  • grid dimensions
  • cool newbie tricks, and stuff like,...when you wouldn't want to be snapped to the grid
  • setting weird grid stuff in UnrealEd Advanced Options

Note there's also Grid

Related Topics


I've just done a little experiment with the UT Jailbreak map LostFalls, to see just how much of a difference to build time the grid makes... the original portion of the map (off-grid) and mine (clean) have nearly the same number of brushes, around 270.

  • Geometry rebuild of my portion: 2 seconds
  • Geometry rebuild of the old portion: 16 seconds

Sorry Dai... :) →Tarquin

SuperApe: I've been having success keeping my red builder Brush on the grid by explicitly setting the Location vector in the Movement properties. If set to vect(0,0,0), I can Build the Brush, keeping the Brush on grid and the pivot is recentered as well. In case I have Snap turned off and accidentally move the red builder Brush, this is how I can "recover" proper alignment. Incidentally, a common error message when placing items says, "Cannot place item, snap to grid may by on". This doesn't mean Snap To Grid must be turned off to place it, it just means the resolution set on Snap To Grid won't allow the item to be placed at that Location (because it's inbetween the Grid lines). You can either lower the resolution on Snap To Grid, or just try to place it in a slightly different location and it will be placed.

Nercury: I think it would be just fine to import Keeping Brushes Snapped To The Grid here.