Unreal Metrics and Specifications - ripped from a HLP file

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Unreal Metrics and Specifications - ripped from a HLP file

Post by Nelsona »

Because questions were asked about the units of measurement used in Unreal Engine 1, I copied some of the information which I found into a folder when I sorted the files after the oldest first.
  • World Geometry

    · 1 world unit = slightly less than 1 inch
    · 16 world units = 1 foot
    · The entire world is 65536 units wide (approximately 1 mile) in the X, Y, and Z directions.

    Coordinate system

    · Z is up, X is north, and Y is east. Coordinates are signed and range from -32768 to 32767.

    Actor Geometry
    Default Player Geometry

    These apply to the woman and man.

    · Player height is 6 feet tall (60 world units)
    · Player's eye is 5 feet above the ground (50 world units)
    · The closest a player can get to a wall is 2 feet (20 world units)
    · The player's head bobs vertically up to plus-or-minus one half foot when walking

    Monster geometry

    Monsters move with physics similarly to the player's, except the following parameters can be changed:

    · How close it can get to walls (player: 2 feet)
    · How tall it is (player: 6 feet)
    · How high a step it can climb (player: 2.1 feet)
    · Its view height when the player is controlling it (player: 5 feet)
    · The maximum slope it can climb without sliding
    · The maximum slope it can climb with sliding

    Metrics and constraints

    · Any step that is 32 (2 feet) or fewer units tall or smaller is climbable.
    · Any step that is 48 (3 feet) or more units tall is unclimbable. Useful for railings and ledges.
    · Try to avoid steps or railings between 32 and 48 units (2-3 feet) tall, because one can’t reliably predict whether a player will be able to climb it or not.

    Doors and grates

    · Do not create grates on the floor where the player can walk. The player will get stuck in them. A grate is an opening that the player can stand on but is too small for the player to fall through.
    · An opening 48 (3 feet) units wide or more is a door and the player can go through it.
    · A player can not go through an opening 32 (2 feet) units wide or less.
    · You can make tricky doorways designed to only let small players through, i.e. doorways less than 32 (2 feet) units wide. If you do this, only do it with a small doorway, not a long passage. If the player barely fits, she can go through a doorway easily but may get stuck on a long passage.


    · For best results, the ceiling should always be at least two feet above the player's head, and it looks best when significantly higher. In regular architecture, ceilings under 10 feet high are uncommon.
    · Don't create ceilings (low doorways or slanted ceilings) where the player can hit his head on the ceiling. Though these situations aren't disastrous, the engine doesn't handle them well and movement becomes choppy.


    · Avoid passages that get progressively narrower if there's a chance the player will get stuck at the end of one. The collision system makes thin passageways difficult to deal with.

    Wedge sides

    · Avoid creating buildings with sides that look like wedges (30 degrees or less). The player gets snagged on these. This only refers to exterior wedges (outsides of objects), not wedge corners in rooms. Wedge corners in rooms are fine.


    · A slope less than 20 degrees behaves exactly like a floor (and is actually considered a floor). Players can move on these without obstruction.
    · A slope between 20 and 35 degrees is a grade. The player can move up these but she slides and must continually struggle to climb to avoid sliding all the way down.
    · A slope over 35 degrees is unclimbable.

    Illumination problems

    As you experiment with lighting, you'll notice some situations that look great and some that look weird. In general, try to avoid the weird looking stuff. More tips to come.

    Texturing constraints

    · In some weird viewing positions, you'll notice textures warping. This is especially noticeable when a polygon is at a very skewed angle. Try to "design around" this. In general, floors and walls look best when horizontal or vertical. Slopes look perfect when far away (i.e. on ceilings), but they warp when the player can get close and view them at skewed angles.
    · Textures tend to look bad (jittery and wavy) when far away. This is especially bad with high-contrast textures. For best results, use low-contrast textures for large things that are often viewed from a distance, such as sides of buildings.

    · Since floors are always viewed at a very skewed angle, low-contrast textures look much better than high-contrast ones. This doesn't apply as much to walls and ceilings.
    · In general, use door frames, railings, and other devices when possible to avoid situations where the player sees textures that are highly sloped.

    Recommended object sizes

    Soon, we'll put together a list of common object sizes (along with brushes for creating things like doors), including:

    · Doors (minimum size, typical sizes)
    · Ceilings (minimum height, typical sizes)
    · Stairways (stair minimum and maximum heights)

    Copyright 1995 Epic MegaGames, Inc.
In general, the chapter "more to come" I do not think it has been of interest, other tutorials that appear in general are also based on assumptions - navigation network really lacks in explanations and has not very true stories. I have seen enough myths about semi-solids, in fact the problems are of a different nature. I'll copy some more later. What I saw and noted refers to geometric corruption in an area that propagates errors further and the Editor tries to cut them to get rid of them, does a kind of reset, but that doesn't really help us.
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Learn the rules like a pro, so you can break them like an artist.
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