Tension Map


(ChrisJones) #1

Hi all,

I’m trying to use this Tension Map add-on with 2.79 but am unable to get smooth results. The usage instructions are scant, as are my Blender skills, so I’m hoping someone might be able to point me in the right direction.

To highlight the issue I’ve used a flat mid-grey image as the displacement/bump map, which theoretically should render smooth. Instead though there are sharp creases along the topology lines where the mesh is being deformed:


Tension Artefacts.blend (567.4 KB)

Additionally, the instructions indicate that the green channel is for squash and red for stretch, however I’ve found the reverse to be true… and connecting the Attribute node directly to the material output results in a blue mesh with pink and cyan deformations instead of black with red and green (as per every demo I’ve seen), which is not helping to inspire confidence…

Thanks for any help!

Chris


Human Progress
(RickyBlender) #2

are you talking about this one ?

have not tested it but check the video it should work

happy cl


(ChrisJones) #3

Thanks for the reply @RickyBlender,

The one I linked to is said to be a patched version of that one. They both have the same creasing problem, although I’ve now found that different builds of Blender seem to dictate the RGB channel order and appearance. I can’t get the original add-on to work properly in the latest experimental build of 2.79, which probably explains the reason for the patch.

I’ve made another test scene (again with flat grey image map), and have noticed that along with the creases there are smaller artefacts that change resolution depending on subdiv level:

Tension%20Artefacts

Tension Artefacts 2.blend (567.3 KB)


(RickyBlender) #4

does it have to be with cycles ?

there is in 2.49 internal tension map function !

did you try to add a sudivi with auto smooth ?

happy bl


(RickyBlender) #5

you did not pack the image in file !

happy bl


(RickyBlender) #6

here is one sample
what are you talking about artifacts ?

za1

happy cl


(ChrisJones) #7

Thanks for taking a look - the image should be in there, it’s just a blank grey one called “Untitled”. It didn’t seem to need to be packed as I tested the .blend file on another PC and the image was there. I’m not sure why yours is appearing smooth… I assume you installed the add-on?

I discovered I accidentally used the Alpha output of the image texture instead of Color on that one, but the results are more or less the same, just more pronounced. Here’s the fixed file, with some dots added to the image (and packed just in case).

Tension Artefacts 3.blend (611.7 KB)

Absolutely!

I did, but there was no difference that I could see.

Thanks again for the help,

Chris


(RickyBlender) #8

sorry I used your node set up only
have to install the addon and test with it

there was a function in 2.49 to do that directly!

happy cl


(ChrisJones) #9

Yes, hopefully that will make a comeback in 2.8 at some point. I find it indispensable for animating organic things…


(RickyBlender) #10

is it necessary to run the script or use use the data already in place in file?
I did not find any video for this
did you try to contact the addon designer ?

thanks
happy cl


(RickyBlender) #11

I found a sort of fake map

happy cl


(ChrisJones) #12

Interesting, not sure I can think of how to translate that into wrinkles based on polygon squash/stretch though.

Just go to User Preferences > Add-ons > Install Add-on from File and select the .zip file, then enable it in the add-on list.

I’ll probably contact the dev unless some solution turns up in the mean time.

(c:


#13

Tension Map functionality definitely needs to be a feature within Blender. I’ve tried to get the tension map addon to work but I feel like I’m missing something and it seemed to be a slow to calculated/update.

@Cesar89 was able to use the tension map addon for doing wrinkles seen in this video.

Another method I found was using Animation Nodes addon, used for motion graphics, it looks very good and should be fast as animation nodes runs real-time. But animation nodes is a beast of it’s own so I’ve never managed to get it to work.


(ChrisJones) #14

Hi Ravenman_13,

Thanks for the suggestion - I did see that tutorial but was scared off by all the scripting stuff… I’ll have another look though and see if it’s as over my head as I first thought.


(pauljs75_) #15

Just wandering through, but could it be an issue because some color socket types apply a scene’s color profile to their output? It was one of the annoying headaches I was running into with vertex color, so you couldn’t use RGB to pass linear value data without having another correction node to account for a gamma curve.

It’s funny that the developers considered it for image output (as color data), but neglected it elsewhere. Would have been nice to have a toggle or just an extra socket.

So if it’s what I think it is, then you’re getting the creases or bumps because with the scene color profile, the actual value data is exponential in some way and ramping up in a compressed manner.


(ChrisJones) #16

Hi pauljs75,

Assuming that’s the case, would you suggest the addition of a node or two with the right values might help? I played around a bit with Gamma and RGB Curves nodes and can get the creases to intensify or move around a bit, but they won’t go away.

Thanks for the response,

Chris


(pauljs75_) #17

Was using it for a completely different thing, but I dug into the problem a bit here:

But none the less if you’re trying to use the RGB values of vertex color to separate how material data is passed over a mesh, it’s not going to work properly for some things with the current behavior.

The work around I had was limited in scope (even changing from default to Filmic also means you had to go tweaking it again), and eventually I came up with some other completely different methods for the particular thing I was trying to achieve.


#18

So I did some advanced googling about using animation nodes for tension map, as the method shown in the tutorial looked very smooth and also runs real-time, unlike the addon which I found ran slow when I used it.

A user on here linked a Blender with the animation nodes tension map stuff working in Blender 2.8.
But mentioned below in link is a issue of the tension map not rendering and only playing in the viewport.


Blend file of tension map the user posted: http://pasteall.org/blend/index.php?id=50966
You need animation nodes for 2.8 for it to work: https://github.com/JacquesLucke/animation_nodes/releases

I did some tests (modifed you’re demo) and end up with still get the same artifacts from it. So it could be the vertex colour problems mentioned. As I found out I couldn’t render the result and only could playback in the viewpoint. Also the tension map addon is able to output weight paint and vertex paint data, where the method using animation nodes only does vertex colour.

These were both viewport renders in 2.8 and not a cycles render.

I also found with the animation nodes method has issues working with a subdivided mesh, as well as rendering the final result.
This was just some rough experimentation on my part, I might test it with 2.7.


(ChrisJones) #19

@pauljs75 Seems like if there’s something to this, it’s beyond my capacity to apply it to tension maps. Still, it was worth suggesting - perhaps it might put someone else on the scent.

@Ravenman_13 Thanks a lot for your efforts there, I guess it’s increasingly sounding like there’s an inherent problem with this sort of thing in Blender.


(RickyBlender) #20

if some one knows how to add this to the list of things for 2.8
it should be added
I don’t know how or where to do that !

thanks
happy bl