4. Tech Stuff! How to build for Blue Mars!

A. The Workflow.

In spite of much misinformation out there, building for Blue Mars does *not* take a high powered 3D program, nor is it very hard.

The workflow is this (and I really broke this out, it's a bit like saying "cut apple, pick up fork, select bite, lift to mouth..."):

a) Make some textures in Photoshop or something.

b) Draw a 3D object with the free Google Sketchup.

c) Texture it up in SketchUp.

d) Export it from SketchUp (essentially a 'save' option)

e) Import it using the Blue Mars Item Editor.

f) if you have leased a block of land, you can set out items on the land parcel (block) with the Blue Mars block editor.

g) then you upload the land parcel (block) and it will be uploaded with the next city update.

Best of all, even if you *haven't* leased some land, you can still set your items out in a city of your own imagining, with the City Editor.   Then take it public later, either with your own city or land rented in say... Caledonia!

B. HOW TO BUILD for the very beginner.

So... how hard is Google Sketchup?

Answer: Not Very!  Two minutes into this eight minute youtube presentation, you'll probably get the idea.  Sure, it takes maybe twenty minutes before the camera controls are second nature, but conceptually, Google SketchUp is ridiculously easy.  Watch and see!

Create a Chair

Texturing things up isn't hard; there's a 'paint bucket' in SketchUp and you just click the faces you want textured; loading new textures, scaling loaded textures and other functions are in there too.  If it's a problem for people I can post more YouTubes, but it's scarily intuitive.

C. What you should download and try, step by step.

Let's get a bit technical, with some clear examples too.

Step 1: Make sure you have a Blue Mars developer account, and the free tools installed.

Sign up as a developer for free at


...and then load the developer tools here


...and install them, of course.

Step 2: Download a validated version of SketchUp

As with anything, there are 'little glitches' that can cause lots of problems ~ let's get around them.  As of today (20 Dec 09) the latest version of SketchUp 7.1 has some collada format export issues that don't quite match up with the Blue Mars import process, so I recommend getting SketchUp 7.0, which you can still get here:

SketchUp version 7.0.10247


Step 3: Beginners should download this for a clear example to play with

Here's an example file, one I made myself with SketchUp in just a few minutes.  Yep, it's just a sign ~ have fun with it!

You can download the Google Sketchup (.skp) file of it, plus all the textures and so forth, here:


Step 4: Read the import instructions

For step by step instructions of how to export something like this from SketchUp, and import it into Blue Mars, read this:


As of 20 Dec 2009, when importing within the Item Editor, some people have found issues with the 'confirm' button and suggest using the 'overwrite' button instead.  Don't worry about it, just press 'overwrite' when importing (both choices come up) and you'll be fine.

Step 5: Place your item in the world, just offline for starters

Notice you put your files for import into your Blue Mars city dev tools directory, under the "MyData" directory.

Fire up the Blue Mars city editor, and open a .cry file like AR_BeachCity under the AR directory.  Don't worry if it throws a few errors on load, this isn't a big deal.

Go to the RollupBar on the right, choose the MyData directory, and drag and drop the info sign into the world.  And there you go :)

Ultimately, if you rent a block of land, you'll do the same thing, just with the Block Editor instead of the City Editor.  There will be a white line around your block (land parcel) and within that area you can put out your items.

When done, you'll take the resultant build created in the block editor and upload it, so it can be pushed to the city.

D. What it's really like.

Okay, teaching someone to drive might amount to a whole lot of words on a page, but once you've driven around a bit it's really nothing to hop in the car and go.  You don't think about the steps of getting your keys, opening the door, &c &c.

What I found, is that the natural building workflow boils down to this:

a) Make whatever scene elements I want in one big SketchUp file.  For instance: roads, lamp posts, walls or whatnot.

b) Every once in a while I'll save and import the entire set of items just to make sure I didn't do anything wonky in SketchUp.  The Blue Mars import process doesn't like, for instance, a single drawn line that isn't the edge of a polygon face, which SketchUp allows.  You gotta kind of try to mess up like that, but sometimes it happens.  Saving a SketchUp backup periodically, and testing import every once in a while, is your friend.

c) Splitting the items into their own separate files (lamp post, sign, road, wall &c) and then importing the items in to Blue Mars format in batches of 10 or 15 items at a time (remember I validated the whole scene, so I know they will all import just fine).  Remember the cryengine doesn't like to have more than about 16,000 non~vegetation items to deal with, so, if you are going to lightly dust a scene with 3,000 snowflakes, it might be best to not make them individual snowflakes and use another technique, like uploading a sketchup geometry that might represent 100 snowflakes.

e) Set stuff out in the city editor or block editor as I like, and save the file.  Usually I put a date and description on it, like say B_Caledonia20Dec09g.cry or something like that.

And that's what it's like!

If anyone has questions or comments, contact desmondshang 'at' gmail 'dot' com ~ if you are doing your own thing I'll help a bit so long as I'm not overwhelmed, and if you are renting from me I'll do near heroic measures, though a skype call should be more than enough to get you going.

Hope this helped!