Hello!

I have come to this strange thing when using a very simple mesh as dynamic dress...

Seems as if the fabric has "internal" fights and show these zig zags... I have tweaked this mesh in many ways, also the settings... and I always see the same weird effect.

I also made a retopo of the mesh and did another mesh with similar shape and it happens... not exactly the same but similar...

Somebody have any clue???

Fabi

I think this is because a mesh bends at the edges - with a regular grid-like flow of edges, bending against that flow will cause this sawtooth effect. Two suggestions - either increase the overall density of the mesh, or use subdivision (P10/PP2014 or via Snarly's Subdivider script for earlier versions of Poser).

Thank you!

I found out that this effect almost dissappears in a whole when: you raise the Stretch Resistance to about 140 instead of the basical 50... or you change the mesh making just loop selections and divide these facets by the half untill you get the resolution you prefer. That seems to homologate the internal tension and delivers a more smoothed folding effect. Still annalyzing it but I think I am on the good road :D

     Granting that it doubles the poly count, try triangulating the mesh and run another dynamic simulation.

found that, and discussed it (with BB, in this forum) some years ago.

further investigations, conclusions and solutions can be found in my tutorial series on cloth room: www.book.artbeeweb.nl/?book=cloth-room. Part III (which is the "how to get your PhD in Poser Cloth Simulation", so do have some asperines at hand) especially chapters 3.3, 3.4 about.

For short: this crumbling is a sort of "mechanical resonance" in the simulation (math details in part V of the tutorial, it's completely), which becomes noticeably apparant in quad meshes, at low vertex density (#verts per cm2), at low friction (esp fold resistence). 

Hence, as the suggestions and findings above reveal: it helps to lose the quads and do triangles instead, it helps to increase vertex density by subsividing, and it helps to raise the resistance although Fold Resistance is more effective than Stretch (as the crumbling is a folding issue, not a stretching one). 
Triangles will make the cloth behave more like linen instead of rubber (eg woven instead of non-woven), while increasing vertex density or raising resistance will make the cloth behave thicker and more rigid.

have fun! 

aRtBee I am reading your pages with a massive attention and I am so so so gratefull for you posting this... thank you!!!!!

You're welcome. You can download the PDF, when that's more convenient.

Just for some enlightenment, entertainment or complete confusion a note on the workings of Cloth Room, behind the screens.

The mechanism simply takes the mesh as it comes, and interprets vertices as "balls" and the edges that make the polygons as "springs". This literally makes a mechanic balls & springs network. Gravity and airflow/resistance make external forces on the balls, and the springs make internal forces. From all that, simple highschool (Newton) mechanic laws are applied, moving the balls and stretching the springs. That is done in discrete steps, each step processing all vertices once, in some U,V order. Then all positions and speeds from all balls are determined, forces from the springs are known, and the next pass starts. You can set the number of steps (per frame) in the sim properties.

The mechanic net is simulated with reallife parameters. One frame lasts 1/30 sec (whatever your animation settings), gravity is downward 9.8 m/s2, and so on. Only, the sim works with grams and cm (given its Spanish origin). As a result, some cloth parameters can be obtained from real life measurements. On the other hand, figure movements should match real time as well. Movements and clothing types that don't combine in real life, tend to wreck cloth sims as well. You can't get properly seated in 0.03 sec while wearing tight thick leather pants, for instance.

have fun 

Very interesting aRtBee, as usual ... I see you've worked on your tutorials again.  Always a learning experience!

well, as per Renderosity request (BasicWiz) I created a rather complete section on Poser Materials. Unfortunately he didn't get it hosted on the Rendo site itself so I had to put all the stuff on my site only, which unfortunately puts it a bit out of sight for a lot of users and forum visitors.

After that, I did the documentation on Snarly's EZMat plugin. At the moment I'm into the Poser-to-Octane and Octane-materials area. That will add another section to the Missing Manuals, in due time.

see ya ! 

Let me see if I can get a "sticky" started for tips and tricks.  It will be a few days before I can work on it ... but I will, and your site will be right up there ... with bb's and snarly's and a lot of others!

I have some other info to add to this thread about strange things happening on meshes used as dynamic elements.

Finally I re-made the mesh, tryied the triangulation in different ways as allowed the UVMapper Pro, and it didn´t worked and the rendered image was showing more artifacts and lines than the previous made with quads.

So I came back and re did the quad's mesh and got much better results, maybe some unexplainable thing changed and the mesh behaved as expected, using normal and subdivided rendered image.

So well, I mapped it. As is a dress, I made 2 halfs and mapped them with zero distortion.

Back in Poser, I made a couple of morphs to add volume, like Width and Extended Bottom. All good, simulation went fine, changed a couple of values as following the ARtBee tutorials and all was good.

So... I got a nice simulated dress, and a nice looking mesh. As I was working still with the Medium Res mesh, I let it to render with subdivision in 1.

Spawned the morph, just to save and compare with different settings, and the the mesh BROKE IN THE TWO HALFS THAT HAS THE UVMAP. I mean, when the morph spawned is applied, is all good, but when the mesh is back to normla, with dynamics dial in zero, it is broken. I noticed that deleting and undoing it returns the mesh in normal way, and saving and loading again, too. But this is very strange!!!!

So I went and made simulations with other merchant dresses and it happens in the same way. I tryied this in 2 different computers and happens the same. Not sure if is my POser copy or if someone else had this occurance... any advice on that?

I can say that this started after the mapping. When testing the mesh before the mapping, nothing happened. I think that as it had not any UV maps the breaks couldn´t follow any path but even I can recognize the way the breaks appear or where, it has no reason.

Gurus there, any help on this??? or is just another Poser weirdness????

this is out of my league, we do need some or our mesh-makers or pro-morphers here: PhilC or Vilters or ...

Ok thanks calling in the extra forces to help on enligth this corner : D

Vilters asked me to show this to him so I think would be good to post it here also, just in case someone sees it and can send some ideas about.

Thank you all for the input and help!!!!

An issue I've been coming across lately is what looks like screen tearing when I have different levels of subD for preview and render set on a prop, render it and then move it. I've tried several props, both my own and several of the Poser primitives. It disI don't see this with figures, and I've messed around with a bunch of different settings now and having different subD levels seems to be the common factor that causes it. Not reported yet as I wasn't sure if this was something to do with either my install or video card issue.

If your dress prop renders OK it can't be a geometry issue. I suspect this may be a screen draw issue similar to what I'm seeing - if you have different subD levels set, render and then try moving the dress, just using either the x y or z translate dials, what happens in the preview window? Also, does the gap disappear if you change the preview level of subD after rendering?

Caisson:

YES it changes when you dial levels, dissappears and comes back after rendering again.

YES I experienced exactly what you say, with props and figures.

YES it happens on me when I move things with different materials, some props as I have seen.

Fabi - have you seen the same thing happening with figures as well as props? Any particular ones (I've only seen this on props so far).

Apart from that, this does look consistent - anyone else confirm? (hoping Tony/vilters will see this).

Steps to reproduce - 

1. load any prop item

2. set different level of preview and render subD in the Properties pane

3. render

4. moving prop in the preview should give a weird tearing effect.

5. re-rendering will not show tearing, and if the subD level is changed the effect will disappear.

If this behaviour is consistent from other users then I'll report it to SM so they can look into it ...

Yes Caisson I don´t remember now what figure was but it sure happened.

NOT all the props does this, some yes and some others not, or maybe all them do and I just tryied the SubD on these that looked bad... that could be a good point but it sure happened with the teacups and teapot I used in promos of my latest RUGS product.

I am sending an email to Vilters now, maybe he can come and check this :D

Thank you sir :D

Hello all, I am following this tread closely, but have not seen this myself.
I always have SubD at "0" and render at SubD "1".

And I realy need a reproducable case to study.

Sent you all the files you asked me Vilters :D

Fabi - try setting the Crease Angle in Properties pane for the prop to 180 - smooth polygons doesn't need to be ticked, it doesn't appear to make any difference. Render & check if the issue is there. Then set the crease angle to zero, render & check.

If this is consistent (wim & netherworks have also looked at this) the the problem should show up worst when the crease angle is zero and disappear at 180.

NOPE Caisson... that does not change nothing because in this case of mine is a dynamic element, so the smoothing angle only have effect on the default shape, not whith the collisioned or simulated clothing. If we are talking about the crumbling effects, then the solution is use  the morph tool to smooth these, and export the already collided object as a new one, so when you import it then you can smooth the creases using the Crease Angle values.

About the gaps in the mesh, that does not change changing that, at least not in my tests...

Thank you so much to all of you gentlemen for taking the time to check this and try to help this lady in disguise LOL

Have a nice saturday!!!!

Ok, a small update here.
Fabi was so kind to send the obj file and procedure, and the issue is reproducable. See screengrab.
But only the preview is afected, the render is always good.

To reproduce?
Run a default clothsimm.
Then add some morph targets (I added Width1 and Bottom wide)
Then spawn an new Morph target => See my funny name. LOL.

Zero dyanamics, zero the morphs, set your new dial to 1 and testrender.
So far everything is looking GOOD, absolutely NO issues what so ever.

But, then turn your newly spawned dial up or down and you get a preview problem => See screengrab.
Only the preview is afected, the render is always OK.

Unfortunately, something is wrong with the object file, and it is symmetry and UV-map related. (exact reason still unclear)
When I test with a rebuild object flie all is good. To be continued.

I have redid the model now mirroring halfs what certainly is not needed but even that it happens again on me. This obj was mapped in different way and is all nice too but the strange thing keeps happening.

Unfortunately, something is wrong with the object file, and it is symmetry and UV-map related. (exact reason still unclear)
When I test with a rebuild object flie all is good. To be continued.

Just adding a useless two-coppers to the conversation... :)
It may be how the subdividing routine determines how the vertices are ordered and adjacency. I have no idea at all how the subd routine works in the newer versions of Poser nor what they're based on nor what type of subdivision operation they perform. (I use Poser Pro 2012. Yes, I'm three years behind everyone else... which is where I normally am. Going to vote for Mondale in the next election, too, 'cause... Why not? :) )

But, apparently, adjacency is critical in subd routines in something like OpenGL: https://www.cs.cmu.edu/afs/cs/academic/class/15462-s13/www/lec_slides/project2_slides.pdf That may hold true for what's being used in those nice new versions of Poser.

But, some modeling applications have weird issues with vertice orders and mirroring surfaces and such. Now, that doesn't mean they're doing anything wrong, it just means that if something is critically dependent upon them, things might get a bit wonky. (Not much usually reaches that deep into specifics in Poser. Morphs do, however, for example. And, there's a morph issue here, as well, right?) Normally, OpenGL uses vertice order to determine simple stuffs, like face normals, and we can easily see that effect inside the Pose Room. But, let's say that mirroring the object in the program used to create it inverts the order on one axis when it creates a mirror. Welding it to an existing mesh will change the face normals, by simple .obj conventions and, for display purposes, that's not an issue. It looks just fine in the Pose Room and there's nothing much that anyone would normally see in most uses of the object. Normally, when rendered and even for dynamics, that's not an issue, either. (Since, it appears by the above description that the dynamics engine builds it's own deformer cage and performs the operations on it.) But, let's say the subd routine is looking for that specific information for something like calculating adjacency in its subdivision routine. It would do fine when working with everything BUT the vertices on the border of the two "halves." In that region, it couldn't figure out which way was up... or sideways, if it was dependent upon that very detailed, very specific vertice information in the original mesh.

Or, let's say it's using the UV coordinates in a weird way. (I shudder to think why, but I guess it's possible. Doesn't make any sense, though...) We know that, at least in the past, Poser did funky things with the border regions of materials with shaders dependent upon UV values and such, right? (I think.)

I profess to know nothing (This keeps me generally content and happy in real life... ) and I don't have a version of Poser that does subd on the fly like you guys. But, I'd be happy to take a look at a simple object file in order to see if I, in my limited experience and capabilities, could figure something out.

UPDATES ON THIS MATTER:

I have been tested this in all ways untill I decided to try this dress as a hybrid figure as I did many times before and VOILA the strange gaps are GONE!

I fixed some minor issues with the UVs, things that actually didn´t affected the final results but I did it and now that the Skirt is a body part, all seems to be working perfect, using morphs, bodymorphs, and all kind of dynamic tricks as is normal in this type of clothings.

So, I assume that the strange behaviour is more likely on props than figures. I can remember seeing these gaps on some figure in the past months but cannot remember which one, probably was an old clothing, or something like that.

I want to thank to all posting people here that so kindly were helping with this matter.

Greetings for all, from Argentina

Fabi

UPDATES ON THIS MATTER:

I'm glad you got your dress working. I don't have the capability to make use of Poser's subd routine, but I would be interesting in examining the dress object that was posing problems for you, just to see if I could find anything unusual going on with it. I would need nothing other than the object file, I you wouldn't mind someone taking a look at it. (I'd delete it after I finished examining it.) But, if you don't want to share it, that's fine, too. :) There are a number of things that can cause issues with "gaps" appearing in certain components based on geometry, whether they're a figure or prop. Split vertices used to be one of the most common issues, since Poser doesn't like them. Another problem can be seen with soft-shading effects and geometries that don't have edges that are well-defined enough for Poser's soft-shading algorithm to make sense of. In that case, it tends to bork up the edges and, in seriously problematic meshes, the only way to correct it is to turn off soft-shading for that object. (If fiddling with the angle values doesn't help.) But, there are actually several soft-shading effects going on and just unchecking the object's "soft shading" box will not always take care of rendering problems if you you wish to have soft-shading on for other objects in the render. In that case, you usually have to lower the values in the soft-shading options for that object to a very low level. Material nodes sometimes have issues (or used to) generating patterns/procedural textures across geometry and shading groups. And, of course, unwelded meshe portions in a figure can be displaced unnaturally by the rigging in some areas where one would want them to follow adjoining geometry closely.

But, I only have experience with versions up to Poser Pro 2012, so I have no working knowledge of versions higher than that. There could obviously be other issues going on. :)

Thank you Morkonan!!!!

Being honest... I threw it up to the gardens when finally had the thing working LOL... I had about 30 different obj files with minor changes, and when I finally had this figured out I had to clean up the folders or would get totally confussed. So... if I find it in any place I will send it to you but I think I have deleted all these failing things.

Was a very simple thing but seems that is a poser glitch so far. With that obj used as body part even it is dynamic, the troubles are gone.

I found out something interesting too... will post it here and in other thread so people can see it. Maybe is already known, but I just discovered it.

If you have a figure with Subdivision activated for to be rendered with one level of subd, exported morphs or morphed body parts will have the delta data duplicated.

I mean, when loaded the new obj file as a MT, in case you neeeded to export it for tweaking in a modeller, the morph data will be as in "2", not in "1".

Same happens when you export the obj as a new prop obj or new parts for a figure. Delta info is duplicated.