wip Real-Time Body Physics (DirectX 11)

[ATIMKOS]

After instal this mod i can't run game.

[CPVC]

5 hours ago, shadowssss said:

 

i used the .exe to install it, and this keeps happening when i run the game

 

Something is happening that is causing the game to crash. If you choose to send your log file in as an error report, I'll be able to take a look at it and possibly come up with a fix that will be included in the next version of RTBP.

 

You won't be able to play the game with RTBP as it is now, so use the installer to uninstall RTBP and try again after the next version comes out or try an experimental version that might already include the fix.

 

4 hours ago, ATIMKOS said:

After instal this mod i can't run game.

 

Like the other poster I responded to, send in an error report if you want. I might be able to produce a fix that will work in future versions. Maybe try an experimental version or uninstall for the time being.

[CPVC]

 

RTBP v2.2 has been released. This new version has the angular physics I've been showing off. They have replaced linear physics as the new default. You can go back to the old linear physics by disabling angular physics with the "disableAngularPhysics" debug flag and enabling linear physics with "enableLinearPhysics". It's also possible to use both at the same time.

 

Angular is the new default because I think it looks much more realistic and is more similar to the way jiggle physics are done in other games. Let me know what you think, though.

 

https://streamable.com/0ukdjd

 

Another big change is that the command server has been removed. You will no longer be able to use the RTBP Commander to tweak RTBP and should use the internal GUI instead. Just press "F11" in game to open the GUI. Remember that you can right click on a slider to configure its range or to split/join left and right body parts.

 

I am planning on making the internal GUI be able to pop out from the game and have a window of it's own, so those of you who have multiple monitors can have the game in one window and the GUI in the other.

 

Since I made a new lightweight installer that I package with every RTBP release and I've removed support for the Commander, the old GUI tools are now obsolete, so you won't be needing those anymore.

 

I've also implemented some potential fixes for some things I've seen in the log files all of you have sent me. For those of you who weren't able to get RTBP running before, it might work for you now. Thanks to the error reporting, I have a better idea of what I need to do for the next release to get RTBP working for all users. Once again, thanks for your help with that.

 

Some locales have a Sims 4 documents directory that has been translated to their native language. If your computer is set to Spanish, French, German, or Dutch, RTBP should recognize this and select the correct documents directory. The installer, too. I wasn't able to test this, so let me know if it doesn't work.

 

RTBP will no longer look for a "reshade.dll", "ReShade64.dll", etc. to try and load as it's DirectX DLL. ReShade is hooking another DLL now and there is no longer a conflict between RTBP and ReShade. Both can be used together out of the box with no extra configuration needed.

 

It was also brought to my attention that the installer didn't scale with the system font. I believe this is fixed now.

 

The read me has been updated to reflect the changes.

 

Internal GUI improvements.

 

Let me know if anything is broken and I'll get it fixed ASAP. Thanks.

 

Edit: Add this to the bottom of your "Settings.ini" file to go back to linear physics:

 

[rtbp.debugFlags]
disableAngularPhysics = true
enableLinearPhysics = true

 

Edit 2: To see effects similar to what you see in the video above, disable angular limits. Use the GUI to check the "disableAngularLimits" debug flag or add "disableAngularLimits = true" to your "Settings.ini" file under the "[rtbp.debugFlags]" section.

 

Edited April 9 by CPVC

[RyuK_]

21 hours ago, CPVC said:

 

RTBP v2.2 has been released. This new version has the angular physics I've been showing off. They have replaced linear physics as the new default. You can go back to the old linear physics by disabling angular physics with the "disableAngularPhysics" debug flag and enabling linear physics with "enableLinearPhysics". It's also possible to use both at the same time.

 

Angular is the new default because I think it looks much more realistic and is more similar to the way jiggle physics are done in other games. Let me know what you think, though.

 

https://streamable.com/0ukdjd

 

Another big change is that the command server has been removed. You will no longer be able to use the RTBP Commander to tweak RTBP and should use the internal GUI instead. Just press "F11" in game to open the GUI. Remember that you can right click on a slider to configure its range or to split/join left and right body parts.

 

I am planning on making the internal GUI be able to pop out from the game and have a window of it's own, so those of you who have multiple monitors can have the game in one window and the GUI in the other.

 

Since I made a new lightweight installer that I package with every RTBP release and I've removed support for the Commander, the old GUI tools are now obsolete, so you won't be needing those anymore.

 

I've also implemented some potential fixes for some things I've seen in the log files all of you have sent me. For those of you who weren't able to get RTBP running before, it might work for you now. Thanks to the error reporting, I have a better idea of what I need to do for the next release to get RTBP working for all users. Once again, thanks for your help with that.

 

Some locales have a Sims 4 documents directory that has been translated to their native language. If your computer is set to Spanish, French, German, or Dutch, RTBP should recognize this and select the correct documents directory. The installer, too. I wasn't able to test this, so let me know if it doesn't work.

 

RTBP will no longer look for a "reshade.dll", "ReShade64.dll", etc. to try and load as it's DirectX DLL. ReShade is hooking another DLL now and there is no longer a conflict between RTBP and ReShade. Both can be used together out of the box with no extra configuration needed.

 

It was also brought to my attention that the installer didn't scale with the system font. I believe this is fixed now.

 

The read me has been updated to reflect the changes.

 

Internal GUI improvements.

 

Let me know if anything is broken and I'll get it fixed ASAP. Thanks.

 

Edit: Add this to the bottom of your "Settings.ini" file to go back to linear physics:

 

[rtbp.debugFlags]
disableAngularPhysics = true
enableLinearPhysics = true

 

Edit 2: To see effects similar to what you see in the video above, disable angular limits. Use the GUI to check the "disableAngularLimits" debug flag or add "disableAngularLimits = true" to your "Settings.ini" file under the "[rtbp.debugFlags]" section.

 

I updated to the latest version but it appears the issue persists on my end. I've read through the log and it still says "No usable custom D3D11 DLL found. Using system DLL", which makes no sense. I ran the installer and it worked without issues. The DLL is in the correct place.

Log.txt

[CPVC]

1 hour ago, RyuK_ said:

I updated to the latest version but it appears the issue persists on my end. I've read through the log and it still says "No usable custom D3D11 DLL found. Using system DLL", which makes no sense. I ran the installer and it worked without issues. The DLL is in the correct place.

Log.txt 5.38 kB · 1 download

 

That's just the log message I forgot to remove. The code that actually looks for a non-system DLL has been removed, though. As for your issue, I have a theory. Give me a bit and I'll whip up a new DLL for you.

 

Edit: Ok, try this. It just might work:

 

RTBP v2.2~1 2026-04-10.zip

 

Edited April 10 by CPVC

[RyuK_]

41 minutes ago, CPVC said:

 

That's just the log message I forgot to remove. The code that actually looks for a non-system DLL has been removed, though. As for your issue, I have a theory. Give me a bit and I'll whip up a new DLL for you.

 

Edit: Ok, try this. It just might work:

 

RTBP v2.2~1 2026-04-10.zip 2.13 MB · 1 download

 

I don't know what I might be doing wrong. I tried this DLL, tried it on CAS, tried it on live mode, there are still no physics.

Log.txt

[CPVC]

16 minutes ago, RyuK_ said:

I don't know what I might be doing wrong. I tried this DLL, tried it on CAS, tried it on live mode, there are still no physics.

Log.txt 6.37 kB · 0 downloads

 

Alright, try this. It's not going to work, but it'll point me in the right direction, maybe. Add this to the bottom of your Settings.ini file:

 

[rtbp.debugFlags]
logPossibleInputLayouts = true

 

Try the new DLL with that change to your settings file and post the log file. Make sure a sim is loaded, so just go into Create A Sim. This might give me the information I need to proceed with a fix. Thanks!

[RyuK_]

7 minutes ago, CPVC said:

 

Alright, try this. It's not going to work, but it'll point me in the right direction, maybe. Add this to the bottom of your Settings.ini file:

 

 

[rtbp.debugFlags]
logPossibleInputLayouts = true

 

 

Try the new DLL with that change to your settings file and post the log file. Make sure a sim is loaded, so just go into Create A Sim. This might give me the information I need to proceed with a fix. Thanks!

Alright. I enabled the flag as you requested. Here is the log

Log.txt

[CPVC]

15 minutes ago, RyuK_ said:

Alright. I enabled the flag as you requested. Here is the log

Log.txt 37.02 kB · 0 downloads

 

Alright, I'll see what I can do with that info. Thanks for your help!

[alexlll]

Is it possible to make  work two versions, DirectX 9 and DirectX 11 together. One is responsible for breast physics and the second one, for example, for the physics of the ass.

Edited April 11 by alexlll

[CPVC]

On 4/10/2026 at 9:56 PM, alexlll said:

Is it possible to make  work two versions, DirectX 9 and DirectX 11 together. One is responsible for breast physics and the second one, for example, for the physics of the ass.

 

You mean having angular physics for the breasts and linear for the butt? No, not currently, but that is a good idea. I'll add that.

[RyuK_]

17 hours ago, CPVC said:

 

You mean having angular physics for the breasts and linear for the butt? No, not currently, but that is a good idea. I'll add that.

Since I am having trouble to run the DX11 version of the mod, I would like to see angular physics for the DX9 version too, if possible, since that one still works normally on my end.

[ATIMKOS]

How to change RTBP Commander 10k windows size? In my game it looks like this:

[CPVC]

On 4/13/2026 at 11:19 AM, ATIMKOS said:

How to change RTBP Commander 10k windows size? In my game it looks like this:

 

  Reveal hidden contents

 

 

 

 

 

 

It was supposed to scale with the window size, but I guess I didn't read the ImGui documentation close enough. I think I've got it now. I'll put out an experimental build later today with some other changes and link you to it when it's ready.

 

Edit: Here you go. This experimental version also enables selectively enabling/disabling linear/angular physics per-body part, so angular physics can be used for the breasts and linear for the butt if you desire. They can be split too, so you could have angular for the left breast, linear for the right. Why not?

 

RTBP v2.2~2 2026-04-14.zip

Edited April 15 by CPVC
Add experimental version.

[0Spirit0]

I found a glitch with one top. I'm sending that top and a small video showing the glitch. It only happens when zoomed out.

 

Recorded Videos.7z

[jeno3]

Hi CPVC, I have a question about the current version. The pack contains a D9 DLL; is that for DirectX 9 or 11? Or does it work for both, regardless of what I select in the game?

[jeno3]

...and would it be possible to change the area of effect downwards from the selected area? As soon as I change the level below, the shoulders in the game also sag.

[CPVC]

20 hours ago, 0Spirit0 said:

I found a glitch with one top. I'm sending that top and a small video showing the glitch. It only happens when zoomed out.

 

Recorded Videos.7z 12.78 MB · 1 download

 

That happens occasionally. Until I can find a fix, you might consider disabling butt physics if you can live without them. I'm pretty sure glitches like that are from creating new bones on the fly like butt physics does.

 

14 hours ago, jeno3 said:

Hi CPVC, I have a question about the current version. The pack contains a D9 DLL; is that for DirectX 9 or 11? Or does it work for both, regardless of what I select in the game?

 

No, if it contains a d3d9.dll, that's gotta be the legacy version. You want this one here:

 

https://www.loverslab.com/files/file/14085-real-time-body-physics-directx-11/?do=download&r=2147932&confirm=1&t=1&csrfKey=cb097b74a9e4d67eb44f0c494d6413e7

 

14 hours ago, jeno3 said:

...and would it be possible to change the area of effect downwards from the selected area? As soon as I change the level below, the shoulders in the game also sag.

 

I'll look into it. Maybe there's a way to reliably calculate a pivot position based on the center of the target bone, the vertices they affect and their weights. I'll do some experiments.

[alexlll]

On 4/12/2026 at 7:58 AM, CPVC said:

 

You mean having angular physics for the breasts and linear for the butt? No, not currently, but that is a good idea. I'll add that.

I have a DirectX 9 version that works well with breasts; it's already perfectly configured, and I wouldn't want to change it, but the buttock physics don't work. If I could run both DirectX 9 versions, I'd keep the old one, and DirectX 11 would handle the butt.

[ATIMKOS]

After new update i still have RTBP Commander 10k windows size problem.

[0Spirit0]

18 hours ago, CPVC said:

 

That happens occasionally. Until I can find a fix, you might consider disabling butt physics if you can live without them. I'm pretty sure glitches like that are from creating new bones on the fly like butt physics does.

 

 

I have the butt physics disabled, that is happening with breasts, and specifically with that top that is why I send the top also.
Don't know if this have anything to do with that glitch but I opened the meshes of that top in blender and noticed it does not follow the default skin uv map.

[CPVC]

18 hours ago, alexlll said:

I have a DirectX 9 version that works well with breasts; it's already perfectly configured, and I wouldn't want to change it, but the buttock physics don't work. If I could run both DirectX 9 versions, I'd keep the old one, and DirectX 11 would handle the butt.

 

There is no way to use both at the same time, unfortunately. What version of RTBP DX9 are you using that has the physics you like? I can port the method used in that version to the DX11 version as an alternate linear physics mode.

 

8 hours ago, ATIMKOS said:

After new update i still have RTBP Commander 10k windows size problem.

 

You do? That's annoying. It's working great on my end. Here it is scaled perfectly down to 1024x768:

 

 

I'll take another look at the code and see if there's something I missed.

 

6 hours ago, 0Spirit0 said:

I have the butt physics disabled, that is happening with breasts, and specifically with that top that is why I send the top also.
Don't know if this have anything to do with that glitch but I opened the meshes of that top in blender and noticed it does not follow the default skin uv map.

 

Your top isn't causing any issues in my game. It could have been something else that was bugging out. I'll do more testing, though.

[alexlll]

Will the old settings work if you transfer to DirectX 11? Another request: the font you are using in RTBP Commander It is beautiful, but hard to read. It would be better to change it to a more visible font.d3d9.rar

[asdurgico]

I'm also getting this error with CTD while travelling to other lots and when using the fashion autority mod (entering and exiting the modify in cas feature). I'm using the latest version

Edited April 17 by asdurgico

[CPVC]

Another experimental release for you all.

 

RTBP v2.2~3 2026-04-21.zip

 

On 4/15/2026 at 11:35 PM, alexlll said:

Will the old settings work if you transfer to DirectX 11? Another request: the font you are using in RTBP Commander It is beautiful, but hard to read. It would be better to change it to a more visible font.d3d9.rar

 

The settings ought to transfer over no problem. To use the linear breast physics exactly as they were the DLL you provided, make sure the breasts are set to use linear physics and enable the debug flag "testAltBreastPhysics8".

As for the font, I have changed that. Now that I think about it, it was a poor choice. Not everyone knows cursive. Really, I couldn't have picked a worse font. Whoops!

 

 

Other things:

 

The pivot point or the point the breasts rotate around is now calculated based on the geometry of the breasts, so for breasts that sag downward, the point should be located lower. This hasn't been tested extensively, so let me know if it works.

 

There is now an "Exaggerate Physics" option. When enabled, RTBP will attempt to exaggerate the physics in all the right ways to make for a more pleasant viewing experience. Currently, all this does it make it so upward moments are more powerful, making things more likely to bounce upward sharply, but more will be added in the future. Basically, by enabling this, you're telling RTBP you want less realistic, more fantasy-like physics. Let me know what you think of this and what other parts of the physics could be spiced up a notch.

 

https://streamable.com/34vsbk

(Left, "exaggerate" off. Right, on.)

 

Improved debugging? Looking at the logs people have been sending in and it seems like some of the issues I've been tracking have been fixed, but there's still recurring errors that need to be solved. The debugging has been improved somewhat to give me more informative stack traces.