My map that I am working on is growing fast in file size, not necessarily physical size though.

My d3dbsp file is 8.6 meg right now but as I begin the "planting" phase (grass/trees/bushes) I'm guessing it will begin increasing quickly.

From looking at other custom maps I have downloaded, the d3dbsp file tends to be 3x - 4x the size of the overall iwd filesize.

My question is : what contributes to increasing the file size the most?

a) models
b) prefabs
c) custom work (texture, sound)
d) # brushes
e) terrain patches


I haven't seen more than a comment here or there to warn about over doing it with any of these items but would love to hear from the experienced mappers.

You map is pretty big.... (8.6 MB)
This is different. Because you can have much models and 1 brush or 1 model and much brushes.... When you understand what i mean... My english is not the best of my languages

I think you misunderstood.

my d3dbsp file is 8.6 meg.

In the maps I have downloaded the largest d3dbsp file I have seen so far is over 28 meg in size, but that same iwd file that it is in is only 10.1 meg in size.

I have not yet made an iwd file from my map so I am wondering what components of mapping increase the file size the most?

alpha blending adds alot of file size also

This is a topic I had talked about before, with some mixed results.

Prefabs will start increasing your .map file size quickly. There are ways to trim that. If your map is a MP map, go in and edit the prefab and remove all the SP enities that are in it. There are also prefabs with "Double" brushes. Ask yourself while editing the prefab "Do I really need a "No Draw Portal" brush there? I then recommend saving the prefab under a different name (so if you want to use it again you don't have to go and edit it all over again), and then when you go to put it into your map file, select every thing while you are still in the edit prefab mode and "Copy" it. Then "Paste" it into your map. This helps some.
Brushes, if you make HUGE brushes, it makes your .map file size very big too. keep that in mind.
For the bsp file. Lighting takes up a chunk of memory. Remove lighting you don't need.
Effeciency. Bevel all your brush sides that join. This is not only for light leaks, but it makes less sides that the program has to paint the textures. Get rid of all mirrored planes, etc.
Bottom line is this: the bigger and more detailed your map is, the bigger the file size is going to be.

andylegate writes...


Thanks for the post, it will help lots.

Can you explain mirrored planes? Not sure I understand what that means.

"Mirrored Planes" are where you have two or more brushes intersect each other. For example the corner of two walls, but instead of beveling the edges to 45 degrees, or "T" them, you have one brush going into or through another.

Your structured brushes (IE Caulked walls, ceilings, etc) you don't want to do this as it will give you lots of errors during compile time. If you have too many, your map won't compile at all.
Non-structured brushes (IE Water textrues, decals, etc.) you can intersect with terrain, walls, etc, and you won't get that error due to the nature of the brush being a Non-structured brush.

The other reason you want to bevel the ends (just like you would if you were buiding something real out of wood) is because normally you are going to just texture one or two sides of the brush, the sides the player can see. If you "T" or "L" the walls instead, at least one of the walls you'll have to texture the ends, and that is more sides of a "polygon" that the computer has to compile during compile time, and more that the game has to "Paint" when your running the map.

Beveling is just a good habit to get into, it can make your mapping time slow at first, but the proffesional result is well worth it. After a while of mapping this way, it'll become second nature to you.
Good luck!

What are the limits / average size of a .map file before you can expect to compile? I started on an outdoor map with a lot of territory. Someone had suggested using 256 x 256 with a detail setting of 15. This, quite unsuprisingly, has lead to a giant .map file size (38,270 KB) I got a MAX_MAP_VERTICIES error when compiling (I expected something of the sort. The map is not far from the size of Bocage.)

I'm begining to trim down the size I'm down to (23,905 Kb) I'm about 40 - 50% of the way thru trimming the ground mesh detail.

How far down do I need to go?

edited on Jul. 4, 2006 01:34 am by DarthBrooks

man, just saw this thread... /oops

here's my take on this :

it's the amount of textured surfaces that counts. nodraw textures (and caulk) and not drawn ingame (removed by the compiler) so therefore I believe they are not as important as the textured ones.

I really don't see why one big brush would be worst then several small ones. if the result is the same ( = one big wall with one texture on it ) then the size associated with that wall should be the same (imo).

here's what I do to "control" the size of my map (I might be wrong here too... be warned). knowing that the game takes everthing as a bunch of straight surfaces (one wall = one straight surface, one curved wall = a bunch of straight surfaces), I am simply trying to limit the amount of structural surfaces. in fact I noticed detailed stuff takes less space than structural stuff. (I reduced the size of my map just by doing that) so everything that curves, has lots of non-linear surfaces -> detail. make sturctural brushes (the one that blocks tris ... explained in portal tuts) real simple. all in all, even tho the amount of stuff counts (alpha blending has lots of patchs, models, etc) I believe the most important factor to size are "cells control" (i.e: carefull portals, correct detailing). having lots of wicked structural stuff (as explained in the sturc/detail tutorial for UO) will produce a bunch of cells you don't want, thus increasing the size... beside giving you bad fps too ...