wip Real-Time Body Physics (DirectX 11)

[CPVC]

6 hours ago, Ofanichan said:

 

RTBPLogs.txt 6.58 kB · 0 downloads

 

Ok, thanks. That all looks good. Try running "D:\Steam\steamapps\common\The Sims 4\Game\Bin\TS4_DX9_x64.exe".

[Ofanichan]

1 hour ago, CPVC said:

 

Ok, thanks. That all looks good. Try running "D:\Steam\steamapps\common\The Sims 4\Game\Bin\TS4_DX9_x64.exe".

So I launched the game like that, it's still the same. I am still getting "unable to connect" messages and clicking "start the sims" on the commander still says "unable to determine"

[CPVC]

3 hours ago, Ofanichan said:

So I launched the game like that, it's still the same. I am still getting "unable to connect" messages and clicking "start the sims" on the commander still says "unable to determine"

 

Hmmm... Any error messages pop up when you run "TS4_DX9_x64.exe"? Do you see the RTBP logo in the upper left part of the screen in game when you start it?

[Ofanichan]

16 hours ago, CPVC said:

 

Hmmm... Any error messages pop up when you run "TS4_DX9_x64.exe"? Do you see the RTBP logo in the upper left part of the screen in game when you start it?

No, sorry.. It doesn't look any different to when I launch it through steam, when I run it like that

[CPVC]

3 hours ago, Ofanichan said:

No, sorry.. It doesn't look any different to when I launch it through steam, when I run it like that

 

Huh, it seems like the EXE isn't picking up the DLL. Usually when a required DLL is in the same directory as the EXE, it'll load the local one first. Maybe there's some sort of security policy in place that is preventing this from happening? Try running "TS4_DS9_x64.exe" as administrator.

 

That or maybe try this: https://superuser.com/a/1503101

 

Maybe that'll do it. I wish I could be more helpful, but it appears that you're doing everything right.

[Ofanichan]

2 hours ago, CPVC said:

 

Huh, it seems like the EXE isn't picking up the DLL. Usually when a required DLL is in the same directory as the EXE, it'll load the local one first. Maybe there's some sort of security policy in place that is preventing this from happening? Try running "TS4_DS9_x64.exe" as administrator.

 

That or maybe try this: https://superuser.com/a/1503101

 

Maybe that'll do it. I wish I could be more helpful, but it appears that you're doing everything right.

I am already running it as an administrator sadly, no difference :c And that link honestly seems too big brain for my feble mind hahah.
I think I'll have to hold on to this until you get to fix that pesky bug and try again then

[CPVC]

While I'm still hunting down that last little annoying bug, I'll let you guys play with what I have so far. This is extremely experimental and only meant for people that know what they're doing. Test this at your own risk, backup your saves, etc., etc., etc. Don't be surprised if something unusual happens.

 

In this ZIP file, you'll find a "d3d11.dll" file. Put that in your "...\Game\Bin\" folder and execute "TS4_x64.exe" to start the DX11 version of the game.

 

Breasts appear to work flawlessly, but the butt causes some visual glitches. This is the bug I've been trying to squash. Oh, and for some outfits one of the butt cheeks is deflated. Another thing I need to fix. Ball physics are completely disabled. Those need some work.

 

RTBP Commander will work with this build, but some of the commands have not been implemented yet. Adjusting the variables will work, though.

 

Once I've taken care of the bug, I'll start adding everything back and put out an official release. After that, the DX9 version will be depreciated and all new work will go towards the DX11 version.

 

RTBP DX11 Preview 2025-10-18.zip

[alexlll]

After I got everything up and running, I tried setting it up. While the breasts react well to the slider movements in static mode, their movement is almost invisible in dynamic mode, so I'm sticking with the old version.

 

Spoiler

 

версия игры 1.113.277.1030 Log.txt версия игры 1.118.257.1020.txt

Edited October 18, 2025 by alexlll

[CPVC]

1 hour ago, alexlll said:

After I got everything up and running, I tried setting it up. While the breasts react well to the slider movements in static mode, their movement is almost invisible in dynamic mode, so I'm sticking with the old version.

 

  Hide contents

 

версия игры 1.113.277.1030 Log.txt версия игры 1.118.257.1020.txt

 

Huh. Make sure you're running the latest version of the Commander.

[alexlll]

It turns out I accidentally deleted part of the previous message. It said I tried RTBP on both the old and new versions of the game. It didn't work on the old version, but it works fine on the new one. That's why I've attached two log files.

[CPVC]

1 hour ago, alexlll said:

It turns out I accidentally deleted part of the previous message. It said I tried RTBP on both the old and new versions of the game. It didn't work on the old version, but it works fine on the new one. That's why I've attached two log files.

 

Oh, I see what you mean. Well, I developed this version of RTBP around the 1.118.257.1020 version, so the older version must be different enough that the new RTBP won't work with it. So, I guess make sure you're running the latest version of the game for the new RTBP to work.

 

Patches are free, right? So someone with just the base game can update to 1.118.257.1020, no expansion packs required?

[alexlll]

I made a short comparison of DirectX 9 vs. DirectX 11.

In Direct X 9 the breasts move and can be adjusted using the sliders. Direct X 11, the breasts don't move and can only be adjusted for height using the sliders.

 

[CPVC]

14 hours ago, alexlll said:

I made a short comparison of DirectX 9 vs. DirectX 11.

In Direct X 9 the breasts move and can be adjusted using the sliders. Direct X 11, the breasts don't move and can only be adjusted for height using the sliders.

 

 

Seems to be working on my end. Anyone else having problems?

 

Are the commands going through? In the Commander, you should see the response from RTBP in the log terminal. For example, changing the spring k value should output 'Spring "female left and right breasts", variable "spring k" set to "200"'.

 

Also, I saw this in your log file:

[RTBP.DBUG (Settings::load/INIReader::parse) 00:00:2.77 1] Successfully read 1 sections with a total of 11 entries.

 

It should say "read 10 sections with a total of 117 entries". Is your settings file correct? Also, I notice that RTBP is reporting that you don't have any debug flags set in your settings file. If you were using alternative breast or butt modes before, those don't appear to be getting loaded anymore.

 

I'm not certain what the problem is. 99.9% of the code is identical to the DX9 version, so they should behave identically. I'll check the old source code and see if I missed something.

[alexlll]

Are the commands going through? 

- Every movement of the sliders is noticeably reflected in the shape of the breasts in the game, which means they work.

 

Also, I notice that RTBP is reporting that you don't have any debug flags set in your settings file.

-Yes, I had to modify the setting file and without this, DirectX 11 version would not launch. I am attaching the modified file. When I first launched DirectX 11, the log file and setting ini file were not created in the rtbp folder. I had to add them manually.

 

I'm not certain what the problem is. 99.9% of the code is identical to the DX9 version, so they should behave identically.

-The thing is that I observed a similar problem in previous versions of DirectX 9, so I chose the one that works correctly for me and I'm sticking with it. I'm attaching the version that works correctly.

Desktop.rar

[CPVC]

15 hours ago, alexlll said:

Are the commands going through? 

- Every movement of the sliders is noticeably reflected in the shape of the breasts in the game, which means they work.

 

Also, I notice that RTBP is reporting that you don't have any debug flags set in your settings file.

-Yes, I had to modify the setting file and without this, DirectX 11 version would not launch. I am attaching the modified file. When I first launched DirectX 11, the log file and setting ini file were not created in the rtbp folder. I had to add them manually.

 

I'm not certain what the problem is. 99.9% of the code is identical to the DX9 version, so they should behave identically.

-The thing is that I observed a similar problem in previous versions of DirectX 9, so I chose the one that works correctly for me and I'm sticking with it. I'm attaching the version that works correctly.

Desktop.rar 4.36 MB · 0 downloads

 

Ah, ok, I think I see what's going on. The version of RTBP you are using is v0.4-p8. I checked the old source code and the breast simulation method you you like had been removed in later versions. In this build I've added it back. Enable the debug flag "testAltBreastPhysics6" to use that method.

 

RTBP DX11 Preview 2025-10-21.zip

[alexlll]

The thing is that rtbp for DirectX 9x works for me with "testAltBreastPhysics3", but in the DirectX 11 version this flag doesn't work.

The additional flag you added in the latest version works. But it works if you additionally enable the "enable Slow Motion flag", this is great news. Now you can adjust the breast movement!

If anyone is interested, here are my settings.

Settings.rar

Edited October 22, 2025 by alexlll

[HentaiGai]

So excited to try this, thank you for releasing the preview to play with!!!

 

Not sure why, but I can't seem to get it working, I completely removed the old RTBP installation for DX9, added in the new d3d11.dll and ran it, Sims started up fine and loaded into the CAS but the commander wouldn't connect.

 

I tried adding the RTBP and RTBP Mod folders back in from v0.4-p9-e1 and with those folders in place, I couldn't get past the loading screen on startup, just sits there with the green diamond spinning...

 

Any help on what I might be doing would be greatly appreciated!!!

Edited October 22, 2025 by RealSiViX

[CPVC]

16 hours ago, alexlll said:

The thing is that rtbp for DirectX 9x works for me with "testAltBreastPhysics3", but in the DirectX 11 version this flag doesn't work.

The additional flag you added in the latest version works. But it works if you additionally enable the "enable Slow Motion flag", this is great news. Now you can adjust the breast movement!

If anyone is interested, here are my settings.

Settings.rar 497 B · 3 downloads

 

The meanings of the "testAlt*" debug flags might change between releases. It depends on what I'm testing at the time. In previous releases, "testAltBreastPhysics3" might have been the same method as "testAltBreastPhysics6" is now.

 

Anyway, I'm glad it's working for you. I'll make sure to keep this flag in across releases and not change it.

 

5 hours ago, RealSiViX said:

So excited to try this, thank you for releasing the preview to play with!!!

 

Not sure why, but I can't seem to get it working, I completely removed the old RTBP installation for DX9, added in the new d3d11.dll and ran it, Sims started up fine and loaded into the CAS but the commander wouldn't connect.

 

I tried adding the RTBP and RTBP Mod folders back in from v0.4-p9-e1 and with those folders in place, I couldn't get past the loading screen on startup, just sits there with the green diamond spinning...

 

Any help on what I might be doing would be greatly appreciated!!!

 

Make sure you're executing "TS4_x64.exe", not "TS4_DX9_x64.exe". Also, make sure "DirectX 9" is not checked in the options, under the "Graphics" section. If all is well, the game should pick up the DLL and work. This build will not show the logo like the DX9 version. I haven't implemented that yet.

[HentaiGai]

3 hours ago, CPVC said:

Make sure you're executing "TS4_x64.exe", not "TS4_DX9_x64.exe". Also, make sure "DirectX 9" is not checked in the options, under the "Graphics" section. If all is well, the game should pick up the DLL and work. This build will not show the logo like the DX9 version. I haven't implemented that yet.

 

I figured it out!!!

 

Turns out, the new version still requires the old dx9 dll, I put the old dll back in the folder and it started right up, have only tested in CAS but looking good so far, thank you again!!!

 

[yokozii]

On 10/21/2025 at 9:49 PM, CPVC said:

 

Ah, ok, I think I see what's going on. The version of RTBP you are using is v0.4-p8. I checked the old source code and the breast simulation method you you like had been removed in later versions. In this build I've added it back. Enable the debug flag "testAltBreastPhysics6" to use that method.

 

RTBP DX11 Preview 2025-10-21.zip 6.74 MB · 34 downloads

so I've tried to install the preview version. the issue i think is happening is when the commander is saying will not connect and needs a RTBP ZIP to install and connect RTPB to sims4 it is ONLY allowing you to pull files from the zip file on the download page..which is the v0.4-p9 with the DX9 stuff inside and i think it overrides the new RTBP DX11 10-21-2025 because it still pulls in the DX9 files from the zip. I got that it installed properly when using the installer but won't work and when I added the d3d11.dll and changed to reshade.dll because I use reshade it didn't work still. my issue now is trying to use RTBP and run the game without reshade. but even if i re-add the copy of d3d11.dll and remove the reshade.dll the game gives me an error and won't start saying missing files. unless I rename it  reshade.dll

..so i think the install is my issue because maybe i should try without reshade but idk?? I tried the both 10-21-2025* and 10-18-2025 DX11 with the *debug . 

I never had an issue with installing RTBP like this. am i missing something ? or what did i do wrong here

RTBP Installer Log.txt RTBP Mod Log.txt

[CPVC]

49 minutes ago, yokozii said:

so I've tried to install the preview version. the issue i think is happening is when the commander is saying will not connect and needs a RTBP ZIP to install and connect RTPB to sims4 it is ONLY allowing you to pull files from the zip file on the download page..which is the v0.4-p9 with the DX9 stuff inside and i think it overrides the new RTBP DX11 10-21-2025 because it still pulls in the DX9 files from the zip. I got that it installed properly when using the installer but won't work and when I added the d3d11.dll and changed to reshade.dll because I use reshade it didn't work still. my issue now is trying to use RTBP and run the game without reshade. but even if i re-add the copy of d3d11.dll and remove the reshade.dll the game gives me an error and won't start saying missing files. unless I rename it  reshade.dll

..so i think the install is my issue because maybe i should try without reshade but idk?? I tried the both 10-21-2025* and 10-18-2025 DX11 with the *debug . 

I never had an issue with installing RTBP like this. am i missing something ? or what did i do wrong here

RTBP Installer Log.txt 7.49 kB · 0 downloads RTBP Mod Log.txt 1.75 kB · 0 downloads

 

Sorry, I forgot to mention that the experimental DX11 DLL isn't meant to be used with the installer and it won't work with ReShade.

 

This will need to be manually installed. Copy "d3d11.dll" to your "...\Game\Bin\" folder, don't rename it to anything else, and run the game in DX11 mode. Launch "TS4_x64.exe" and make sure DX9 mode is disabled by unchecking the "DirectX 9" option in the settings under the "Graphics" section. You'll need to restart your game after this.

 

This experimental preview release isn't really ready for prime time, it's not feature complete and it is buggy. It's just what I have so far. It does work, but I recommend sticking with the DX9 version for now.

[jeno3]

Hi CPVC,

 

everything looks good to me so far with the Dx11 version, except for the problems you mentioned. I'm still having the issue that the breast physics doesn't work with all the implants, but I guess I'll have to live with that. I think it depends on how much you change the mesh. Could you show me the range of mesh size that the breast physics works with? Then I can make sure to stay within that range in the future. The breast physics doesn't work for seniors, do you know about that?

 

I'm attaching some Blender files for you. Maybe you can see something. The original mesh is always the same one I'm working from. It's interesting to see that with the old RTBP (DX9), number -2- worked, but now it doesn't. I'm still trying to accommodate user requests, but I just can't get number -1- to work with RTBP.

 

Oh, I can't attach Blender files here. I'll send them to you separately.

[jeno3]

2 minutes ago, jeno3 said:

Hi CPVC,

 

everything looks good to me so far with the Dx11 version, except for the problems you mentioned. I'm still having the issue that the breast physics doesn't work with all the implants, but I guess I'll have to live with that. I think it depends on how much you change the mesh. Could you show me the range of mesh size that the breast physics works with? Then I can make sure to stay within that range in the future. The breast physics doesn't work for seniors, do you know about that?

 

I'm attaching some Blender files for you. Maybe you can see something. The original mesh is always the same one I'm working from. It's interesting to see that with the old RTBP (DX9), number -2- worked, but now it doesn't. I'm still trying to accommodate user requests, but I just can't get number -1- to work with RTBP.

 

Oh, I can't attach Blender files here. I'll send them to you separately.

 

Blenderfiles_.rar

[HentaiGai]

7 hours ago, jeno3 said:

Hi CPVC,

 

everything looks good to me so far with the Dx11 version, except for the problems you mentioned. I'm still having the issue that the breast physics doesn't work with all the implants, but I guess I'll have to live with that. I think it depends on how much you change the mesh. Could you show me the range of mesh size that the breast physics works with? Then I can make sure to stay within that range in the future. The breast physics doesn't work for seniors, do you know about that?

 

I'm attaching some Blender files for you. Maybe you can see something. The original mesh is always the same one I'm working from. It's interesting to see that with the old RTBP (DX9), number -2- worked, but now it doesn't. I'm still trying to accommodate user requests, but I just can't get number -1- to work with RTBP.

 

Oh, I can't attach Blender files here. I'll send them to you separately.

I have had none of the problems you have mentioned. Breast physics has been working fine for me on all breasts, including large breasts and seniors...

 

Make sure you have installed RTBP v0.4-p9-e1, including the d3d9.dll and then install the new d3d11.dll, also make sure that you are actually running the dx11 version of the game.

[CPVC]

On 10/30/2025 at 1:44 AM, jeno3 said:

Hi CPVC,

 

everything looks good to me so far with the Dx11 version, except for the problems you mentioned. I'm still having the issue that the breast physics doesn't work with all the implants, but I guess I'll have to live with that. I think it depends on how much you change the mesh. Could you show me the range of mesh size that the breast physics works with? Then I can make sure to stay within that range in the future. The breast physics doesn't work for seniors, do you know about that?

 

I'm attaching some Blender files for you. Maybe you can see something. The original mesh is always the same one I'm working from. It's interesting to see that with the old RTBP (DX9), number -2- worked, but now it doesn't. I'm still trying to accommodate user requests, but I just can't get number -1- to work with RTBP.

 

Oh, I can't attach Blender files here. I'll send them to you separately.

 

Yup, I'm aware that elder sims don't work. Right now, RTBP only looks for adult male and female sims. It can differentiate between the two by looking for male and female features in the mesh. Female sims have breasts and butts that protrude further than male sims. Male sims have broader shoulders than female sims.

 

In the future, I'll add elder and teen sim detection and you'll be able to customize physics based on age. I think teens work fine because they line up well enough with adults. I'll have to examine the meshes to see what to look for when detecting teens.

 

The rays I'm using for breast detection originate from (0.023, 0.351, 1.0) and (-0.023, 0.351, 1.0) in direction (0.0, 0.0, -1.0) for the left and right breasts. This is in game space. Converted to Blender space, that's (-0.092, -4.0, 1.4) in direction (0.0, 1.0, 0.0). RTBP assumes that the bones with the most influence are the breast bones.

 

So, for RTBP to work, the mesh needs to be identifiable as female and the closest vertex on the triangle the ray intersects with has to have the breast bones as the most influential bones.

 

As for your second mesh working in the DX9 version of RTBP, I examined the old source code and I did tweak the ray origins slightly between that version and the DX11 version. It used to be (0.022, 0.35, 1.0) as the origin, now it's (0.023, 0.351, 1.0). That might have been enough to make your mesh not function with RTBP anymore.

 

I'll look into a better way of detecting breasts that accommodates more variation in breast positions. Right now things have to line up fairly well with the default meshes. I've already got a couple ideas.

 

Attached is an image of your first mesh and where the ray would intersect it.

 

 

Edit: Whoops, forgot to mention another thing RTBP does when creating breast bones. In the event that the two bones gathered from the initial ray casts against each breast are equal, it'll go with the first pair of bones that are not equal. For example, if both breasts are influenced by the spine bone and their respective breast bones, but the spine is the most influential for both, RTBP will go with the ones that are different, the left and right breast bones.

Edited October 31, 2025 by CPVC