Hey, I'm incredibly new to modding the Sims and I don't know my way around this whole deal yet, so please bear with me if this is in the wrong place or the answer was right under my nose or something. (Sorry in advance if so!)

I'm wondering how one would go about changing the graphics for street art in University Life, ie. replace the Maxis-made graphics that your sim sprays onto walls in-game with your own images. I used to do something similar with making custom graphics for the graffiti function in games like Counter-Strike and Team Fortress 2, but I don't know how it's done in the Sims and I can't seem to find any info on how one would do it.

From what I can gather, it sounds like the S3PE program might be what I'm looking for... but I'm a little lost on exactly what I need to do with it, or if what I want to do would even involve that program or not.

Yes, you can use S3PE and a paint program that handles DDS-format graphics to replace the default street art images with your own.

All of the images are stored in the "FullBuild_p18.package" file that holds the rest of the resources for the University Life EP. You should be able to find this in the "C:\Program Files (x86)\Electronic Arts\The Sims 3 University Life\GameData\Shared\Packages" folder. Make a copy of it in a working folder somewhere else to play with.

Open that package file in S3PE and sort the list of resources by name. Not quite halfway down you'll find some _IMG resources such as "high1x1MuralA_1_0x3484e3243be9f3f7", "high1x1MuralA_2_0x3484e3243be9f3f4", and so on. When you click on these, you should see a preview of image over on the right side of S3PE. If you don't, look under the Settings menu and checkmark the "Enable DDS Preview" item.

If you don't care about the nitty-gritty details, skip down to the How To Change section below.


Some Background Info

The _IMG resource names follow this format:

QualitySizeMuralVariation_Stage_FNVHashOfName

For example, high1x1MuralA_1_0x3484e3243be9f3f7 is the image used for a high-quality, 1x1 square (small size) mural, the first random variation, during stage one of the painting process. The number after that is an FNV64 hash of the name "high1x1MuralA_1". You'll see it's the instance number over in the 5th column in S3PE and it's the key the game actually uses to find the resources it needs.

The same mural images appear to be used for both wall and ground murals, subject to some tuning restrictions in the StreetArtVariants XML file, and the specific variation is randomly selected by the game when a mural is begun.

The painting process goes through three stages. 1 = a basic roughed-in outline of the mural with the tape border, 2 = a more filled in image, still with tape border, and 3 = final image without tape border. The final image remains as the finished mural in your town. There is an additional image, identified as stage _4, which is a partially wiped-away image used when a sim carries out the 'Clean Up' interaction.

So each mural must have four image resources. They are all DDS format, with the final _3 stage image being twice the size of the others. For example, 1024 x 1024 instead of 512 x 512 for the large size mural. You can preview these stages by clicking on each _IMG resource in S3PE.

The Quality level can be low, med, high, or master for masterpieces. Scroll down through the list in S3PE to see the resource names starting with those.

Size can be 1x1, 2x2, or 3x3 for small, medium, and large. Not all sizes are used everywhere. For example, low quality murals only come in small and medium sizes.

According to the game's code, it will use up to 10 variations labeled A through J although there are some tuning restrictions discussed below.

Browsing through FullBuild_p18 you'll find some more _IMG resources which follow a similar naming scheme but without Mural in the title. Those are the images for graffiti.


How To Change The Default Images

There are a few different ways of approaching this, but since you're new to S3PE I'll try to describe a method which may be slightly longer but hopefully keeps things straight.

1. Create a working folder if you haven't already. In S3PE, right-click on each _IMG resource you want to change and select "Export >" "To File..." from the context menu. Save it using the default magic name to your working folder. Repeat for each of the "high---", "low---", "master---", and "med---" mural _IMG resources. Ignore the _IMG resources which do not have the word "Mural" in them for now, those are for graffiti. Once you experiment with murals, you'll be able to do the same thing with graffiti later if you want.

2. So you've now got a folder full of DDS images. Use your paint program to modify them, following the same sequence of 4 painting stages for each mural as described in the background info above. When you save your modified version, be very careful not to disrupt the magic file name. You can add something like "_ver2" right at the end to keep them organized but keeping the rest of the name as it is will make things much easier in the next step.

3. Once you've edited the images, it's time to assemble them into a package the game can use. In S3PE select "File" "New" to create a new package. Under the "Resource" menu click the "Import >" "From File..." item. Select each of your modified files and click Open. In the next dialog box, make sure the "Compress" and "Use Resource Name" boxes are checked then click Import. In the list you should now see your _IMG resources, each with the same name and more importantly the same Instance number as the original since we're replacing the game's default images. The magic file name for each DDS image is what allowed S3PE to automatically fill in the correct information.

4. Save your new package, calling it whatever you like. Maybe something like "MyInitials_StreetArtFancyMurals.package".

5. Put the package in your game's Mods/Packages folder. If you haven't used Sims 3 mods before, be sure to set up your game to accept them. Follow the steps in this wiki page: http://www.modthesims.info/wiki.php...g_Package_Files

6. Test in-game. If you have started by only replacing a few of the images initially to see how they work out, remember to have your sim select the correct size and that they have a high enough skill level to paint, for example, the high quality murals. Even then, the game will randomly select which mural to paint, so testing can be a bit hit-and-miss.

That's the basics. If you get sick of your modified images, just remove your package file from your game's Mods/Packages folder and any existing murals in town will revert to the game's standard graphics.


Adding Non-Default Murals?

What I described above is a method to change the default murals. It would be nice if we could add our own images rather than just overriding the defaults but so far I haven't been able to do so.

The tuning file which tells the game what murals are available is the StreetArtVariants XML file found in the GameplayData.package. It contains a number of sections like this:

I believe the Level0 through Level10 entries form a weighted scale indicating how likely a sim will paint a mural of the specified quality and size at a given Street Art skill level.

The SmallVariations, MedVariations, and LargeVariations entries would seem to indicate how many variations are available as _IMG resources for this specific mural quality and size. Note that even though the same images are used for both wall and ground murals, sometimes the number of variations indicated in this tuning file differs, presumably so that, for example, more variations can be painted as ground murals than as wall murals.

The game will select a variation randomly after determining what quality and size the sim will produce.

Given this information, it would seem possible to add non-default murals by increasing the number of variations specified in the XML tuning file and adding the corresponding _IMG resources following their standard naming scheme. For example, since the last medium-quality, large-size mural variation is 'F', we could add _IMG resources...

med3x3MuralG_1
med3x3MuralG_2
med3x3MuralG_3
med3x3MuralG_4

...being careful to use the proper instance ID (FNV64 hash of resource name) and then change the tuning file's <LargeVariations> entry from 6 to 7.

Tried it, doesn't seem to work.

Great fun to test as well. Since mural variations are selected randomly, your sim may have to paint quite a few before one of your custom versions is used. When the game appeared to choose one of my additions, it either jumped out of the interaction entirely or seemed to generate a blank mural.

If you want to dig into it further, check out the code in Sims3.Gameplay.Skills.StreetArt and Sims3.Gameplay.Objects.HobbiesSkills.GraffitiSurface.

WOW. Thank you so much for such a thorough and detailed answer, I really appreciate it!!! I'm going to try this out soon, it sounds like it will be a lot of fun.

No problem, hope everything works out for you. Sorry it took over a month for you to get a response to your original post, but I don't drop by this part of the MTS forums too often.