uFlex - NVidia FLEX for Unity3D - Unified Visual FX [RELEASED]

This is a nice implementation of Flex in Unity. I am having a bit of trouble understanding how to get a uFlexFluid to interact with a terrain and other objects. I am pretty new to Unity... is there something I am missing?

Any examples out there on how to setup something like shown in the video below or better yet even is this particular example available for download somewhere?

 

Hi, Korzen, Thanks a lot for making this great tool.

(1) I have modified FlexParticlesLock.cs to make the flag cloth to follow the pole's movement. Currently in the sample scene of the flag attached to a pole, if the pole object is moved (by mouse drag or script, or animation etc.) the flag cloth will stay in the old place.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections.Generic;
3.  
4. namespace uFlex
5. {
6.     /// <summary>
7.     /// Lock particles which are inside the collider
8.     /// WARNING. Tearable cloths will cause wrong behaviour
9.     /// </summary>
10.     public class FlexParticlesLock : FlexProcessor
11.     {
12.         public bool m_lock = false;
13.         //public float m_markerSize = 0.3f;
14.         public bool m_followAnchorMovement = false;
15.         public float m_weightMultiplier = 0f;
16.  
17.  
18.         public List<int> m_lockedParticlesIds = new List<int>();
19.         public List<float> m_lockedParticlesMasses = new List<float>();
20.  
21.         public List<Transform> m_lockedMarkers = new List<Transform>();
22.  
23.         public override void FlexStart(FlexSolver solver, FlexContainer cntr, FlexParameters parameters)
24.         {
25.             for (int i = 0; i < cntr.m_particlesCount; i++)
26.             {
27.                 Collider collider = GetComponent<Collider>();
28.                 Collider[] colliders = Physics.OverlapSphere(cntr.m_particles[i].pos, 1.0f);
29.                 foreach (Collider c in colliders)
30.                 {
31.                     if (c == collider)
32.                     {
33.                         m_lockedParticlesIds.Add(i);
34.                         m_lockedParticlesMasses.Add(cntr.m_particles[i].invMass);
35.                         cntr.m_particles[i].invMass = 0.0f;
36.  
37.                         GameObject lockedParticle = new GameObject("lockedParticle_" + i);
38.                         lockedParticle.transform.position = cntr.m_particles[i].pos;
39.                         lockedParticle.transform.parent = this.transform;
40.                         //JointMarker jm = lockedParticle.AddComponent<JointMarker>();
41.                         //jm.markerSize = m_markerSize;
42.                         m_lockedMarkers.Add(lockedParticle.transform);
43.                     }
44.                 }
45.             }
46.         }
47.  
48.         FlexContainer curr_cntr;
49.         public override void PostContainerUpdate(FlexSolver solver, FlexContainer cntr, FlexParameters parameters)
50.         {
51.             curr_cntr = cntr;
52.             for (int i = 0; i < m_lockedParticlesIds.Count; i++)
53.             {
54.                 if (m_lock)
55.                 {
56.                     cntr.m_particles[m_lockedParticlesIds[i]].invMass = 0.0f;
57.                     if(m_followAnchorMovement)
58.                     {
59.                         cntr.m_particles[m_lockedParticlesIds[i]].pos = m_lockedMarkers[i].position;
60.                         cntr.m_particles[m_lockedParticlesIds[i]].invMass = m_lockedParticlesMasses[i]* m_weightMultiplier;
61.                     }
62.                 }
63.                 else
64.                 {
65.                     cntr.m_particles[m_lockedParticlesIds[i]].invMass = m_lockedParticlesMasses[i];
66.                 }
67.             }
68.         }    
69.     }
70. }

(2) If anyone wants to make other collider types (box, sphere, capsule, etc.) interact with uFlex particles, you can write a small script to add a mesh collider to those objects and disable the old colliders. This operation must be done before the line in FlexColliders.cs, where mesh colliders are searched and saved for updating collisions with uFlex particles.

(3) Any chance to integrate this? https://forum.unity3d.com/threads/uflex-soft-body-animation.438952/ Basically it will enable a model that's playing a animation or moved by script (not by gravity at all), to interact with other uFlex particle objects. Right now we have rigid, soft body, cloth, fluid, rope. I will really apprecite it if a new uFlex object type can be driven by animation, but do physics collisions with existing uFlex objects.

Thanks a lot in advance. ^_^

 

@AKQJ10 Thanks for sharing this, will have at this.

 

@AKQJ10 Tribute to you, sharing makes uflex stronger, learn from you!

 

I am running Unity 5.5.0f3 and a blank project with only this included and running a sample scene just crashes. I made the changes requested by the readme as well. Any help here would be appreciated, or at minimum what version of 5.5 is stable. Thank you!

 

HI, please reinstall the NVidia graphics drivers even if you have got the latest one. During installation select Advanced and Clean settings option. It works in 99% of the cases. Please let us know if it also worked for you.

 

hi,korzen
i bought your plugin yesterday.thank you for your amazing plugin.
im developing a liver simulation application.i generate a softbody by you plugin,but i dont know how to interact with this softbody.for example:i use a small pole to stab the liver,the liver should be depressed.
i dont know how to implement this simulation,could you help me?

 

You need to model your pole as a uflex rigid body or add a mesh collider to a regular pole mesh. I think the former can be more robust, but try both approaches

 

@korzen303
//FlexSolver.cs line 210:
void FixedUpdate()
{
Flex.UpdateSolver(m_solverPtr, Time.fixedDeltaTime * m_fixedTimeStepMult, m_solverSubSteps, IntPtr.Zero);
}
Change To:
void LateUpdate()
{
Flex.UpdateSolver(m_solverPtr, Time.fixedDeltaTime * m_fixedTimeStepMult, m_solverSubSteps, IntPtr.Zero);
}

FPS much higher. In Uflex5.5,You don't Change!

 

thank you for reply
how to control uflex rigid body by mouse.
.the uflex rigid body just dropped and stay on the ground,i cant move it

 

Hello @korzen303 , any way that FlexColliders only takes a specific mesh and not all those that are in the scene automatically? , I put the mesh that interests me but the script automatically puts all of the scene

 

@AKQJ10 Give me your email.Please.

 

in FlexColliders:: ProcessColliders(IntPtr solverPtr, Flex.Memory memory), the line of m_meshColliders = FindObjectsOfType<MeshCollider>(); is where mesh colliders are searched and saved in m_meshColliders. You can do a name or tag matching to pick the colliders you want. Warning: don't try to add other types of colliders here, like m_cubeColliders = FindObjectsOfType<CubeCollider>(); then use the same logic to compute collisions with uFlex particles. It's not that simple, I have tried.

 

Thanks for answering AKQJ10

 

1.would it be possible to create uflex soft particle without mesh, Put them at position of some mesh, And then remap Flex particles to the near mesh?
2.Areas of influance for Mesh. For example different colors of particle would have diifrent influance on soft mesh. 0 would have no effect on mesh at all.1 full inluance, 0.5 Interpolation between Uflex, and skinned mesh renderer

 

I'm having a strange issue with the soft bodies... for some reason every time I instantiate a new one, any previous one I made disappears. This only happens with the soft bodies, not with rigid or cloth... Very strange... any suggestions?

 

@korzen303
Hello! Do you have any tests showing how well uFlex works with long ropes? Is it possible to simulate a rope with length of 300 meters, that collides with itself and rigid bodies? Does it support rods and variable length ropes?

 

This is so cool. Pity it only works on nvidia on windows and not all platforms. :-(

 

@korzen303 is it possible to use uflex for clothing like tshirts? I tried a few meshes in the cloth tool but they seem to just explode and drop to the ground. I thought perhaps it's because of internal collisions due to the wrinkles that is part of the mesh, so I turned off interaction type to none but the results are the same. What are the tricks/limitations of using uflex with mesh clothing for humans (non-plane)? Thanks!

 

I was wondering if there is a way to trigger audio with uFlex. I can successfully make audio trigger from collisions in Unity, I just can't seem to get them to correspond to the uFlex objects. When I add a collider to the object, it responds but doesn't follow the uFlex object around as a parent, it ends up displacing on its own independent path. Any suggestions?

 

Hi, I am having some problems scaling down a fluid simulation. Which parameters should I be looking for?

 

Same problem here. I ended up scaling up my scene but now I am having loads of collision problems.

 

I have a dynamic mesh created by a script in my scene. When my uFlex fluid particles hit the mesh they freeze and I get the following error:

eFlexLogError: Cuda error: 4 in cudaMemsetAsync(s->mStaticContactCounts, 0, n*sizeof(int8_t)) [FILE: ../../flex.cu: 4466]
UnityEngine.Debug:LogError(Object)
uFlex.FlexSolver:ErrorCallback(ErrorSeverity, String, String, Int32) (at Assets/uFlex/Scripts/Solver/FlexSolver.cs:311)
uFlex.Flex:UpdateSolver(IntPtr, Single, Int32, IntPtr)
uFlex.FlexSolver:FixedUpdate() (at Assets/uFlex/Scripts/Solver/FlexSolver.cs:212)

Actually cuda errors such as this just repeat endlessly after the collision.

Any ideas?

 

Scaling is not an option for me

 

I was trying FleX cloth for awhile. I found that it works great against other FleX objects but doesn’t really work with moving PhysX objects or when setting the particle mass to 0. If the cloth explodes without collisions then it’s probably a scale issue. I think each vertex in the cloth is a particle and each particle defaults to a radius of 1 meter. You probably want about 50 cm spacing between each vertex.

I prefer to keep the default FleX settings and just treat one unit as a centimetre. If I need to use PhysX then it’s probably easier to modify the PhysX settings.

I also added a bone rotations fix for “uFlex soft body animation”.

 

Video link:

[/QUOTE]
Anyone has standard unity shader with improvments from minute 29?

I wrote something like this, from video, maybe sombody can make it work:

Code (CSharp):

1. Shader "Custom/shaderflexmoj" {
2. Properties {
3.         _Color ("Color", Color) = (1,1,1,1)
4.         _MainTex ("Albedo (RGB)", 2D) = "white" {}
5.         _Glossiness ("Smoothness", Range(0,1)) = 0.5
6.         _Metallic ("Metallic", Range(0,1)) = 0.0
7.     }
8.     SubShader {
9.         Tags { "RenderType"="Opaque" }
10.         LOD 200
11.      
12.         CGPROGRAM
13.         #pragma multi_compile _ _DYNAMIC_VERTICES
14.         #pragma vertex vertForwardBaseDynamic
15.  
16.         // Physically based Standard lighting model, and enable shadows on all light types
17.         #pragma surface surf Standard fullforwardshadows
18.         #pragma target 3.0
19.  
20.         #ifdef _DYNAMIC_VERTICES
21.           #include "../dodatki/DynamicVertices.cginc"
22.             VertexOutputForwardBase vertForwardBaseDynamic(VertexInput v, uint vertexId :SV_VertexID){
23.             TransferStandardDynamicData(v, vertexId);
24.             return vertForwardBase(v);
25.             }
26.             #else
27.             VertexOutputForwardBase vertForwardBaseDynamic(VertexInput v){
28.             return vertForwardBase(v);
29.             }
30.             #endif
31.         // Use shader model 3.0 target, to get nicer looking lighting
32.  
33.  
34.         sampler2D _MainTex;
35.  
36.         struct Input {
37.             float2 uv_MainTex;
38.         };
39.  
40.  
41.         half _Glossiness;
42.         half _Metallic;
43.         fixed4 _Color;
44.  
45.         void surf (Input IN, inout SurfaceOutputStandard o) {
46.             // Albedo comes from a texture tinted by color
47.             fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
48.             o.Albedo = c.rgb;
49.             // Metallic and smoothness come from slider variables
50.             o.Metallic = _Metallic;
51.             o.Smoothness = _Glossiness;
52.             o.Alpha = c.a;
53.         }
54.         ENDCG
55.  
56.     }
57.     FallBack "Diffuse"
58. }

also made made txt file changed to cginc

Code (CSharp):

1.      int _firstVertex;
2.          StructuredBuffer<float3>POSITIONS;
3.          StructuredBuffer<float3>NORMALS;
4.          StructuredBuffer<float4>TANGENTS;
5.  
6.          void TransferStandardDynamicData(inout VertexInput v, int vertexId)
7.          {
8. vertexId += _firstVertex;
9.          v.vertex.xyz=POSITIONS[vertexId];
10.          v.normal=NORMALS[vertexId];
11.              #ifdef _TANGENT_TO_WORLD
12.              v.tangent.xyz=TANGENTS[vertexId];
13.              #endif}

As you might guess it does not compile.

Also on the video at 31min Flex particles are asigned to the nearest skinned mesh vertexes, therfore He can animate main model with cloths(maybe he has made only an empty shel made from flex particles), then these Flex particles might have zero invere mass which is important for uflex Cloth settings...
It would be pretty nice if uflex got a function like that,of creating uflex particle for skinned mesh characters where uflex particles are asigned to movig mesh vertexes with 0 mass.

 

Hi there. Curious about grabbing this.
Is it possible you could list what version of Flex you're currently utilizing?

 

Hi, Korzen, Thanks for the great tool.
I am now implementing small size of water pond and having a fluid-leak problem. Many particles are tunneling through the pond wall. As I read Flex reference manual, I should set FlexParams::mEnableCCD. Please teach me how to set this parameter.

 

Is there any problem with using this asset in VR?
I'm building a room-scale game that could use flex.
I've seen someone write a comment about this not being usable in VR but no reply.

 

Unfortunately, I am going to have to change my original assessment and flag this thing as far from ready for prime time. The examples do work... sort of. If you look closely in the authors's demo video you see water spilling through the bowl. Uflex objects and unity object interaction is completely broken. I get cuda errors the minute my flex object hits a mesh if I am lucky and a complete Unity crash if I am not. Multiple questions post here by myself and others and no response from the author. I have dual GTX 1080s with the latest and greatest drivers. Sorry but in it's current state this is not worth anything near $30.

 

@djrosu Sorry, to hear that things are not working well for you. Could you please send me the problematic scene and I will have a look. I didn't have any complaints about problems with uFlex stability from others.

@vice39 uFlex works with VR. Two things, the Screen Space Fluid rendering works only in Double Pass VR rendering. Flex is heavy on the GPU and you may quickly run into performance issues. The dual GPU (non-SLI) config may help (see post
#103)

 

@jun-oishi FlexParams::mEnableCCD is in the docs but not in Flex 1.0 API so uFlex can't use it. I will report this issue to NVidia guys.

 

@korzen303 Can you comment on whether or not this asset will work in VR ?

 

@vice39 It works

 

@korzen303　Are there any version updates?

 

@ccc7861 I am working currently on SDF support. The rest of Flex API is already covered. Over the next months I will improve tools to e.g. easily hook up flex stuff to skinned renderer. I also plan to improve screen-space fluid rendering

 

@korzen303 great! SDF? JAPAN SDF?

 

It's great to hear it. I would like to have leak-free particles, and if possible please add smoke sample.

 

I decided to purchase this to do a few tests in VR. ( HTC Vive )

The sample scenes run fine but are scaled way to large... the developer needs to scale down by approx. 80 times.

I tried scaling up the Steam V.R camera 70 times and then the scene looks much better... but being so large the physics are a bit slow due to time & spatial distance.

makes me think perhaps he's got his scale setup in preferences set too high.

If I load one of the sample scenes ( Fluid sim with Chinese Rubber Dragon ) & drop in a standard Steam V.R camera & then hit play, The dragon looks 20m high

each particle = 1m spheres

So that's my only concern is the scale of scenes... they are huge. Sure hope the Dev. can scale everything down or supply a simple fix.

Q. How can I turn meta-balls into an actual single smooth surface ? Do I apply a material or is there simply a setting I need to change to have particles converge more ?

My Specs: GTX980 i7 6700K 32G Ram

 

Hi Banksy,

yeah I will scale down the demo scenes for the next release.

Check the Screen Space Fluids folders and provided examples for an experimental smooth fluid surface rendering.

 

Nvidia Flex 1.1 now supports Direct Compute, so it is available for all DirectX 11 cards !!!
But NvFlexDemoReleaseD3D_x64.exe crashes every time on my GTX 660, however CUDA version (NvFlexDemoReleaseCUDA_x64.exe) run excellent (my graphics drivers are up-to-date).

https://developer.nvidia.com/flex

 

Hi, yes I am already looking at upgrading uFlex to Flex 1.1. For DX it seems that Flex needs to hook up to the Unity's DX11/12 rendering context, which may require more work than CUDA version.

 

Do you know wen you are goint to release it? looking foward to use this on VR

 

I still can't believe that they haven't released any information about the smoke examples. They were doing that back in 2014. I have written them to see if they ever plan to release this.

 

Hello,

I recently purchased the uFlex asset, I am liking it so far I am just wondering if there is any way to change the size of the particles. I have seen some other people mention this issue. I am trying to simulate granular materials like boulders and gravels but the default 1 m particle size is too large for the simulations I am running and scaling up all of the other objects seems a little backwards to me.

Particle size aside, I was wondering if there is some documentation available on the various flex solver parameters that isn't the tool tips? The particles seem very 'bouncy' to me, and I haven't been able to successfully reduce this using any of the parameters. When I drop volume of particles, if any of them are alligned directly over top of eachother, they bounce in vertical stacks, before eventually settling and rolling off of each other, which seems to be a bit unrealistic.

Any help would be greatly appreciated, thanks again!

 

@digableMatt Seems like NVidia moved their CFD solver to NVidia Flow, which is not yet publicly available.

@cheesydongboys In the included Flex manual there is a documentation how the collision works in the solver. I will prepare more small scale examples. Currently there is one in the Unfiied Examples, have a look. Basically, all the solver parameters are just scale down x100 times.

 

@korzen303 Thank you for the reply, I am successfully creating smaller particles now and they look great.

I am now having some issues with small self-colliding particles slipping through mesh colliders or not responding to them at all. In some cases if I place a collider underneath particles which are about to fall, the particles will fall around and form to the collider, but when I move the collider the particles will hold the shape of the collider, not moving or falling in response to the colliders movement. Any suggestions on this particle behaviour?

 

@korzen303 I actually figured out my previous question regarding the leaking, so no need to follow up on that.

I have just noticed now though that the particles don't seem to really affect non-flex rigid bodies. Rigid bodies falling in my scene are able to affect flex objects, but the flex objects don't have any affect on the rigid bodies trajectory. Is there something I am missing or is this intended to be the case. If this isn't already possible, two-way collisions would be an excellent feature.

 

Is there any chance to get the shades from the Screen Fluids Pro into this asset??

Thanks

 

Does anyone know if it is possible or not to change the velocity of a uFlex object directly? I am instantiating a pre-made block of uFlex particles but I'd like to be able to alter its initial velocity. This would be similar to setting the velocity for an objects rigidbody component, but because the uFlex body does not use ridigbody components I am unsure how to do this.

Also has any figured out how to reduce the bounciness of uFlex bodies. If I drop a uFlex cube from the same height as a regular cube in Unity, I see significant bounce and slight compression in the uFlex cube. Is it possible to make the uFlex cube behave almost identically to the regular rigid Unity cube?

Thanks for any help !