Adding Dual Quaternion support to UnrealEngine4 (Images inside)

funkinfamily

Any Chance you will be able to get a 5.4-mod going? I had tried to cherry-pick your work from ue5-dqs as well as previous branches but was unsuccessful. I would be fine using 5.5 except i am unable to build plugins for that version currenty.

AlienRenders

Sorry for the late reply. I will try to get everything up to date as soon as I can. I think 5.4 just needs to cherry pick an older revision from ue5-dqs but I may have force merged that. I'll check if I still have an older build.

 

 

nabe

While researching Dual Quaternions, I found this topic.
Will it become available in UE5.4 or UE5.5 in the future?

I'm currently using UE5.4, and as I wrote in the last post at the URL below, I'm using a deformer called "DG_DualQuatDefoermerDemo," but I'm having difficulty with production because morph targets can't be used.
https://forums.unrealengine.com/t/dual-quaternion-support/144831/28

It would be great if there was a DQ deformer that could easily use morphs...

Visual Sculpt

Dual Quaternion Skinning has been available in Unreal Engine through the Deformer since it was introduced in the 5.1 Content Examples project. Not long after it was added to the David Vodhanel's updated fork of DazToUnreal. I posted a tutorial recently going over basic export, import, and fixes for using DazToUnreal that includes how to enable it on a character. I have used it with morphs and haven't had issues.
https://www.daz3d.com/forums/discussion/725206/daztounreal-for-ue-5-5-tutorials

Originally, if I remember right, there were 3 versions of the DQS Deformer. First that was just base mesh, second that included morphs, and a 3rd that was supposed to project for clothes but was very buggy. The current Content Examples project seems to have kept just the 2nd version.

nabe

I downloaded UE54win.zip from the URL below and moved "DTU_DQS_Deformer" to my project, and it worked properly!
Thank you very much!

https://github.com/daz3d/DazToUnreal/releases

However, when I changed the Morph Target values, the normals became strange and weird shadows appeared. So I combined "DTU_DQS_Deformer" and "DG_TEST." Since I did this intuitively without proper knowledge, other problems might arise, but the normals are now working correctly.

AlienRenders

Visual Sculpt said:

Dual Quaternion Skinning has been available in Unreal Engine through the Deformer since it was introduced in the 5.1 Content Examples project.

If it works for you, great! It's just unfortunate that it's so badly implemented (slow). For every vertex, it converts all the LS matrices to DualQuaternions and then applies the weights. So if you have 100 bones and 100k vertices, you have 10 million conversions. In my branch, it converts it once (100 conversions) and sends it to the video card. So 100 conversions vs. 10 million. Now, there is the conversion back for the result, but that part is the same for both. It's been a while since I've checked the code in those graphs. Hopefully, if you have limited bone influences, it'll only convert 8 matrices per vertex. But that's still 800,000 vs 100.

I'll try to create a good branch for 5.5 soon. I'm just working on something else right now and don't need DQS atm. The problem is getting the deformer graphs installed. You'll have to manually copy them since UE has a separate script for downloading and installing engine content.

nabe

AlienRenders said:

The bad news is that it would be extremely inefficient. What the "Skeleton" node does right now is execute a shader that reads all the bone matrices that affect ONE vertex (at a time). It outputs all these matrices as Bone Matrix output. It merges them all together according to the bone weights and outputs it as "Weighted Bone Matrix". We can't use this weighted bone matrix as the whole point of using DQS is to have different method of computing the final transform. So I *could* convert each set of bone matrices that affects the vertex. But this would be executed on every vertex. Converting LS matrix to DQS isn't the fastest thing in the world. Doing it over and over on the same matrices would be extremely slow. As a stopgap measure, maybe it would be ok. Dunno.

Just to give a better example of what I mean by inefficient. Say there are 100 bones. And 100K vertices. And you decide to use 8 bone influences per vertex. With the DQS branch, it converts the 100 bone matrices to DQS before sending it to the shaders. Now, it does convert it back, so that's once per vertex. That's 100,100 conversions. I tried avoiding converting back since it just needs to multiply with the vertex position, but I didn't want to mess with the existing shader code.

With the deformer, there would be 800K conversions. These conversions are not simple. And it gets worse for unlimited bone influences.

Looking back at past logs, I see you mentioned this two years ago as well...

I had read it before, but after testing it myself, I finally understand the issue.
When moving simple objects like individual characters, it looks good and works fine, but when placing multiple characters, the performance drops significantly.

Thank you for your advice. And thank you for planning to create a 5.5 branch.
I can't help with development work, but I'll patiently wait for your updates.

Visual Sculpt

nabe said:

I downloaded UE54win.zip from the URL below and moved "DTU_DQS_Deformer" to my project, and it worked properly!
Thank you very much!

https://github.com/daz3d/DazToUnreal/releases

However, when I changed the Morph Target values, the normals became strange and weird shadows appeared. So I combined "DTU_DQS_Deformer" and "DG_TEST." Since I did this intuitively without proper knowledge, other problems might arise, but the normals are now working correctly.

I don't recommend that version, it is very outdated. The fork by David Vodhanel, the original author of the plugin, is updated regularly and the last was just 3 weeks ago. The mainline version from Daz is over a year and a half old and missing a lot that David has done since.

Link to David's fork: https://github.com/David-Vodhanel/DazToUnreal

Follow the tutorial I linked earlier to install it correctly. You don't need to edit anything, just enable the Deformer on the character and it works. There is no performance hit if you are on the newest versions of Unreal, the Deformer has gone through major updates in recent versions. It may take time to process the first time you apply the Deformer, because it is making all the calculations, but once done and cached it is good to go. It does not do all the calculations on the fly as suggested.

 

AlienRenders said:

If it works for you, great! It's just unfortunate that it's so badly implemented (slow). For every vertex, it converts all the LS matrices to DualQuaternions and then applies the weights. So if you have 100 bones and 100k vertices, you have 10 million conversions. In my branch, it converts it once (100 conversions) and sends it to the video card. So 100 conversions vs. 10 million. Now, there is the conversion back for the result, but that part is the same for both. It's been a while since I've checked the code in those graphs. Hopefully, if you have limited bone influences, it'll only convert 8 matrices per vertex. But that's still 800,000 vs 100.

I'll try to create a good branch for 5.5 soon. I'm just working on something else right now and don't need DQS atm. The problem is getting the deformer graphs installed. You'll have to manually copy them since UE has a separate script for downloading and installing engine content.

What you say may have been the case in 5.1 when it was Experimental, but have you tested it in recent versions? Deformer works great now and shows no performance impact. In fact it reduces my frame times by 1ms when applying DQS.

I made a fresh example to demonstrate. It has Kat, Laura, and Ty for G9 all subdivided at level 2 when exported from Daz. Unlimited Bone Influences enabled. Using the MetaHuman Lighting project on the Portrait_RT level. VT used to keep original texture quality with everything still default 4k. You can see enabling the DQS_Deformer somehow improves performance here. You can tell when it's disabled by the pointed deformity between the legs and flattened glutes during the jump landing. Then when enabled those issues are gone and it matches how it looks in Daz using the same animation.

Here is a raw screen recording with DQS Deformer off then on:

As you can see, I'm also running on older mid-range hardware as shown at the end- i5-9600k + RTX 2070. It would run even better if I wasn't screen recording.

And did you ever submit a pull request for your branch so Epic could included it in the engine? If you've got good code changes Epic will incorporate it, there is plenty of code attributed to users. If you did, it may have been implemented and could be why it runs better now.