This is the fourth part of The History of Sonic Adventure DX Modding article. If you haven’t read already the introduction of this article/topic, you can do so by clicking right here. You can find the previous parts as well after that or by checking the end of this page.

On the previous part, the discussed topic was the research done on the protoypes of Sonic Adventure, how these contributed into figuring out more aspects from the Dreamcast version, and the gradual process that was restoring piece-by-piece the original assets into Sonic Adventure DX. This not only involved figuring out the formats of models and sounds, but also finding how to implement them into the DX PC port (which often needed the use of coding).

At this point, everything was building up for what most in the scene had been waiting for, which was restoring what was lost from the Dreamcast game into SADX PC. The culmination of these efforts would arrive as two mods in the 18th anniversary of the original game’s release in Japan: December 23, 2016. The first mods to talk about is the SADX Lantern Engine mod.

This mod restored the original lightning engine from the Dreamcast through the use of an external shader (as described in the previous part), and used the Dreamcast palette files to add colored lightning in each stage (this also meant that you could modify the palete files with a tool to alter the lightning and colors if you wished); it even helps the original untouched SADX levels look much better than normal. And of course, this was received with great fanfare from Sonic Retro members and Sonic Adventure fans, between being an incredible technical accomplishment, and also a huge improvement for the game’s visuals.

I think my favorite mods for SADX are definitely Lantern Engine and Time of Day cycle mod, which changes between day, evening and noon. Lightning and different time of days really bring life to the game.


The second mod would be the culmination of PkR’s previous testorations (as well the idea behind SADX 99′ Edition): Dreamcast Conversion. This very first official release would be made avaliable by PkR on that same day, and featured all the Action Stages with Dreamcast Landtables along with most of the content that was previously released in separate mods. Getting this to happen was an ardous process, between having to fix many porting issues and coding back in previously absent features.

However, getting the DC level functional in SADXPC is only the starting point. The PC version has a lot of not so obvious but very important technical differences, which prevent Dreamcast levels from looking or working correctly, so I had to fix a lot of things. For example, one of the biggest problems I ran into was related to transparent polygons and textures with alpha channels. The Dreamcast’s GPU had a unique hardware feature called order-independent transparency, which allowed Dreamcast game developers a lot more freedom in how they built their renderers and assets in comparison to other consoles and PC games.


To fix that, I made a lot of changes both to the assets themselves and to how the game renders them. For levels and object models, I mostly did it by sorting their mesh order to make sure transparent stuff would always render last. I also hooked the game’s rendering functions for many ingame objects to force some transparent models to render with a specific “depth” or in a specific order so that I could control how they should blend with other models. I learned how to do most of this stuff from SonicFreak94, who was very kind to explain how certain things work, and guided me around the disassembly.

The above is only one example of what needed to be done for SA1 levels to work properly in SADX. There are also collision problems, code bugs in SADX, material issues, different fog settings, things that were removed entirely, the list goes on… Restoring Dreamcast stuff in SADX is still an ongoing process, and we learn something new every once in a while. I figured it out mostly by poking around with code and learning how SADX works from the disassembly. x-hax is a very helpful place to learn about it, too.

Some people might think that Dreamcast Conversion is just a simple texture replacement to make SADX levels look like SA1’s, but there’s a lot more to it. It replaces pretty much every single area in the game, it restores over 800 models from the Dreamcast version, and it contains a large amount of code-related fixes, as well as custom code.


Since then, it would receive countless additions and bugfixes, and another small restoration would SonicFreak94’s Onion Skin Blur mod (which restored Sonic feet on his running animation appearing blurred; a feature only present in the Japanese version of Sonic Adventure).

But on February 2017, ItsEasyActually released a preview video of his planned Dreamcast Character Pack, showcasing one of the game cutscenes, and both Sonic and Tails had their Dreamcast models…but most importantly, it showed Sonic with a working morph head (having a expression in the cutscene), something which had not been managed properly before (JCorvinus’s port didn’t have a morph head), and gave many SADX fans something to be eagerly waiting for.

I had tried to make that mod many times, dating way back to when MainMemory made the first iterations of the SAMDL program. It wasn’t until I saw PkR working on his Dreamcast Conversion that I got back into the scene after a year or two long hiatus. It was early 2017 when I really started developing the mod in full. The Solution file has a date of 1/26/2017 if you want an exact date, haha.

[…] My inspiration behind the Dreamcast Characters was actually wanting to get in on a piece of the restoration at the time which is probably a little selfish sounding, but I have a reason haha. PkR was working on levels, I wanted to do the characters. As I previously mentioned, I had tried numerous times to port the Dreamcast models to SADX over the years prior to the ModLoader. It was one of those things I absolutely wanted to make happen, so as soon as I knew it would be possible, I knew I had to make it happen.


And after many years and attempts to achieve Dreamcast characters in a way or another (from both JCorvinus’s Dreamcast Sonic mod, and the Dreamcast-textured characters in SADX 99′ Edition), ItsEasyActually finally delivered with the release of the Dreamcast Characters mod in August 14, 2017, the last key piece that was missing to finally make SADX look just like it did on the Dreamcast.

Note that just a year before, both Dreamcast stage models and lightning were already restored, so character models finally becoming a reality could deliver something very similar to the original Dreamcast version in the visual department (except upscaled), which could be said that was the main goal behind this long journey. The models had all their proper materials, textures, and were complete with hands and morph heads.

I did get help initially from MainMemory for the Weld Data that would cause the game to crash, and I got some help with SonicFreak94 to fix up a few problems that came from Tails “Jiggle physics.” Specifically his ears and cheek would clip through his face, and SonicFreak94 helped create a solution. I also received help from PkR for ensuring the mod would correctly with the Lantern Engine mod for the most accurate look to its original Dreamcast version. […] The overall mod was difficult at first. I had to learn a lot about programming during it, and I ended up learning a lot more about the game than I expected to. I’m very happy with the final product though.


Of course, the Dreamcast Conversion updates would also deliver many things that were missed on the first mods and releases, like a explorable Chao Race lobby (SADX sent you directly to the SA2-style menu instead of having to push the button in the room), a Dreamcast Title Screen with water ripples (from the international releases), more Dreamcast models, fixed camera in cutscenes, Dreamcast DLCs (mini events and extra Twinkle Circuit tracks that were avaliable in the original through VMU files; these were completely absent from SADX), transparency fixes.

I thought it was great that the Dreamcast version was finally making it to a wider audience, because pre-DC mods it was fading into obscurity. DC characters was a requested mod for a while because it came after the other two – I used to follow IEA’s progress on it, it was pretty good.

I first started talking to PkR when I gave him new graphics for HD GUI, because the ones the mod originally came with didn’t resemble the Dreamcast version’s that well, particularly the monitor and life icons. I ended up doing a good handful of things for that mod, including reshooting every credit image in the game. (We had fun getting those to not double the mod’s filesize)

I also helped out with his efforts on DC conversion sometimes, like if he wanted to compare how an object worked between ports.


There would be other upgrades as well, like the HD GUI mod (upscaled UI elements) and Sound Overhaul, which goes to absolutely great extents to restore everything related to Dreamcast audio (including voice clips), which originally were obtained through sound-extracting tools from the Dreamcast SDK, but were replaced in one of the last updates (in March 2020) with high-quality recordings from the Dreamcast version.

Sound Overhaul is Dreamcast Conversion’s companion mod, it’s like Dreamcast Conversion but for sound. SA1 and SADX have a lot of sound differences which are caused by both programming differences and the format of the sounds themselves. It’s definitely a challenge to make SADX sound like the original game. […]

Versions 1 and 2 of Sound Overhaul relied on a set of scripts (from kingshriek’s page) that rip the Dreamcast version’s MLT files to create miniDSF files, which are playable in Winamp and foobar2000 when you use some specific plugins. But the sound produced by those plugins isn’t accurate to the Dreamcast’s sound chip. […]

At some point I was contacted by Alex/TheLegendOfXela, who had got his Dreamcast modded with DCHDMI for fully digital video and audio. I built a semi-automatic version of the MLT player for him, and he ripped the sounds for me. […] It’s quite involved. It’s kinda like Dreamcast Conversion, with a lot of hacks and fixes for the vanilla game.


The Dreamcast DLC restorations were a bit interesting too; considering how these were exclusive mini-events to the Dreamcast versions (most for the Japanese version only) and that SADX didn’t have almost anything left of them (except leftover music tracks).

Before PkR learned where the DLCs stored the properties of each object, the mods placed them manually in the closest estimated spots. My stuff was helpful in finding out where most of the Y2K Rings were, but it was only a short period before he got the original data and made everything 100% accurate.

I wasn’t the first one to make vids about the DLCs, but I was the only one who covered them all. I had to visit a lot of different sites to track them down, but now they’re all safely archived on Dreamcast Live.


There was one particular DLC that was lost for several years, which Speeps kept tracking down around that time, until he found Moopthehedgehog, which happened to have the DLC in one of his newly-purchased VMUs. While it mostly just added new year decorations in Station Square (each one with a message), it still was a piece of history that was completely lost until that day (and can be seen as one piece of what predated stuff like holiday events in online games nowadays).

My biggest contribution to SA1’s DLC is the Kadomatsu stuff.

At the end of 2016 I noticed one of them couldn’t be found anywhere online (The Kadomatsu New Year pack) and started raising the alarm about it. It was bad, the only real mentions you could even find of it were 20 year old Japanese websites

I had one of my friends write up a Lost Media Wiki article about it (with everything I dug up about it) and I revamped the Retro Wiki page, later adding the part about that particular pack being unobtainable in 2018 after further unsuccessful attempts to find it. I’m glad word got out about it, I can’t believe the 20 year old lost content was found from a guy buying a random VMU!


Hey, that 4X memory card was in pristine condition 😛


However in 2017, ItsEasyActually and supercoolsonic would start a task at revisiting previously attempted concept after further advancements made in Autodemo research and SADX modding tools: Beta Windy Valley.

So, I always had an interest in the original level. I’d always seen the screenshots, the prototype gameplay, I just knew I wanted this level restored in the game. Unfortunately, I always considered it a bit of a lost cause due to the fact that we did not have the level data to work with.

When Orengefox released the AutoDemo to the world, I began digging through the files to see if it was in there. Based on the file date, I knew there was a hope to see it, but I did not have high hopes. Once I got the file open, I was insanely happy to see that it was the actual prototype level. The only disappointing part was that the level itself was lacking its textures. Those are still something I hope we eventually get one day out of another prototype.


While some things were still missing on the original data (like textures and some of the spline data for paths), they were allowed to use some of the assets from JCorvinus’s previous restoration, and the Autodemo data was much more understood at this point.

Not only certain missing textures were redone/recreated, but also some few missing models were recreated from scratch (based on collision data and footage). Almost everything else that was missing or recreated in the original Autodemo restoration was reimplemented with cleaner code and restored data (like floating platforms and camera), thanks to the improved tools allowing the team to obtain proper data instead of using guesswork from scraps of data and beta footage.

It is a much deeper, more faithful recreation that benefits from a far better understanding of the AutoDemo, both in terms of data and code. It also comes with a ‘pure’ version that shows how incomplete the original AutoDemo data really was. My only contribution that project was when they came to me and asked me for the assets and code I had made for my version of the restoration. I gave it to them along with a complete explanation of what I did and why. After that, they took that data an ran with it. I’d say that the results speak for themselves.


With one object in particular, the T_Spring object (yellow spring in Act 2), I ended up making that in Blender. The object is missing its model data in the game, so we took the collective opportunity to develop our own asset using the collision data as a rough guide for the general shape of the object.


Now try to think about everything from where it started to what had been achieved at this point: First it was texture edits and hex-editing models manually, then editing object layouts and rearranging level chunks, to having proper tools for editing levels and models (and early attempts in importing Dreamcast models).

And then finally after more than 10 years, not only the Dreamcast stages, characters and lightning were restored in the 2004 port of SADX, but also this fabled original version of Windy Valley was also faithfully restored, allowing players to experience this lost level after years of only being partially seen in beta footage and screenshots.

What we have seen so far in this journey is that, when someone worked on something as big as Dreamcast Conversion, somebody else got inspired and strived for something else as big, which would also inspire that first person (and many others). Considering how everybody involved are human persons like anybody else, this kind of perspective about people being inspired by others is something I consider important, because you could say that, had it not been for other people being inspired to work in their own attempts, that one that had begun first may have stopped because of a lack of motivation (like with PkR’s attempts back in 2012 and 2014; at least until SADX 99′ Edition and the previously WIP Lantern Engine mod inspired him to work on the concept once more).

In my opinion, Lantern Engine is hands down the biggest achievement in SADX modding ever (other than the Mod Loader itself of course). It’s absolutely incredible and I can say for sure I wouldn’t have made Dreamcast Conversion if Lantern Engine didn’t exist. SonicFreak94 is a genius. I am also very proud to have been involved in Lantern Engine’s development, although SF94 obviously did the main work. Lantern Engine is something I love and care about a lot.

I also love ItsEasyActually’s Dreamcast Characters mod. I’ve always wanted to have Dreamcast characters back in SADX, and he brought them back, complete with proper vertex welding and mouth animations. Back when the mod wasn’t public, a lot of people asked me to add character models to Dreamcast Conversion, but I decided not to look into it because I knew ItsEasyActually was going to do it. I’m happy he delivered such a quality mod. I’ve made contributions to his mod as well, mostly lighting-related, and some code changes/fixes.


I’ve learned so much honestly. I remember starting out learning Blender back in 2005, and I’ve kept up with it as a side hobby that fines its way into the modding world as well when the time is right. Thanks to my knowledge with 3D models from games, I’ve learned a lot about topology, both good and bad. I’ve equally learned a lot about rendering techniques, especially more modern ones with the use of PBR.


X-Hax would also have its own Discord server in May 2018, allowing for a wider range of people integrate to the X-Hax community. It would be bridged with the IRC channel through a bot, allowing IRC users to talk with Discord users and viceversa). It truly had went a long way from the older days, specially when the young SADX enthusiasts and aspiring modders in 2010 had gone through 10 years of life,as well as getting to see SADX modding mature as much as this.

When I started out, I had no idea that a website for a few of my close friends would even evolve into an IRC channel, let alone a Discord server full of people interested in modding SADX. I feel kind of bad, since the community hasn’t really been in my hands since 2010 or so. I would have kept participating if life had allowed me to, but I’m very glad to see that it kept going long after I left. These days I just sit back and watch, occasionally pushing updates to the editor and answering a question or two.


Generally X-Hax is where you learn how to do all that because there’s more resources in there than anywhere, including how to open the disassembly.


But there’s still some more to learn about this journey, and not just knowing about where we at now. There’s still an extra aspect that’s pretty known from the Adventure games that also was explored, researched and modded by fans: The Chao Garden! Since this sort-of side game where you raise Chao also had many avid fans, it would be understandable that there was also an interest in researching and modding Chao-related features…and that did happen. However, that will be a story for the next section…

Thanks for reading the History of Sonic Adventure DX Modding (Part 4)! The original concept was to have all the sections in a single article; but as a way to allow some gradual ease in reading the whole thing, these sections that cover the entire topic will be spread out in separate posts. You can find the next one and all the others in the index below, though note that grayed-out sections are still not avaliable yet (but will be made and released soon enough).

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If you liked my content, sharing this with others helps me out; and you can lend me a hand through my Ko-fi page as well! I was glad to see the amount of positive reception for the last part, and managed to clean this one faster than usual so I hope that you have enjoyed this one! I’m also planning to see if I can give the site a facelift at one point (changing the theme I guess), but guess it will be matter of time to know if I would do it before or after finishing this whole topic.

But until then, see you in the next one!