Displacement Map? sub divsion confusion using SKindigo

[CADMonkey]

Hi I've been trying to play with displacement maps but as per usual I am really struggling.

I'm using Skindigo 3.2.12 with Indigo 3.4

I've been following the Wh447 tutorial on youtube

http://www.youtube.com/watch?v=GCbMX2Ud ... ature=plcp

It works great for the pebble material but when I change it to my ceiling tile displacement things go funny....

I have tried alsorts of sub division settings but always seem to get the same ( or similar) result. Am I doing something stupid?

Is it because my map with mostly flat with just carved lines? I don't know but hopeully one of you will?

[Zom-B]

a exemplary problem report!! Thanks for that, it is a pleasure to (try to) help

For me it seems the view dependent angle is set to low, raise it for some more subdiv in flat areas!
Indigo has issues with view dependent subdiv on the edges of the screen, thats a Indigo bug!
You can see on your colored triangle image that each box that gets cut by the camera edge "looks" funny
Maybe playing with error threshold could help here too (I even don't know what that setting is for -.-' )

[CTZn]

In this case I wouldn't use the view-dependent setting at all but a higher curvature only, with perhaps one more subdivision level once curvature is set to work. At that point the flat areas (almost the full surface) should have much fewer triangles.

[CADMonkey]

Thanks for you input. It is very much appreciated

I will try both approaches

[Zom-B]

In this case I wouldn't use the view-dependent setting at all but a higher curvature only, with perhaps one more subdivision level once curvature is set to work. At that point the flat areas (almost the full surface) should have much fewer triangles.

well thats a "workarround" for that bug. View dependend SubDiv is a awesome feature, that saves tons of RAM...
I think the view dependency should mybe be extended some more over the camera view, so such artifacts doesn't occur anymore

BTW: the "Error Threshold" isn't explained in the online manual: http://www.indigorenderer.com/documenta ... ubdivision

Found something in the technical manual:

mesh :: displacement_error_threshold
Displacement error threshold.
For example, if the displacement texture map specifies a displacement of 0.2 m in the center of a triangle,
and the displacement_error_threshold is 0.1 m, then the triangle will be subdivided
type: scalar real
units: meters
restrictions: >= 0
default value: 0.1 m

is 10cm not a quite high default treshold?!

Here a example of the error in my actual test scene:

[CADMonkey]

Okay.

I have a correct result.

The curvature threshold worked but in the opposite direction suggested?

I have also tried this with view dependant on and off. It produced very similar results.

Pixel threshold seemed to have little effect. I tried from 0-50.

Thanks for you help people. I never expected such prompt and kniowledgable responses

[Zom-B]

The curvature threshold worked but in the opposite direction suggested?

eh, yes... the higher the value the less Indigo subdivs in flatter areas. I would suggest you try a higher value here, since the flat areas of your tiles have a lot of unneeded polys created... the only eat up RAM!

I have also tried this with view dependent on and off. It produced very similar results.

View dependent doesn't subdiv meshes outside of the camera view, so it should look quite the same

Pixel threshold seemed to have little effect. I tried from 0-50.

That is a setting that needs "view dependent" to be active! beware that the pixel threshold is aiming to internal render res, so SuperSampling kicks in! If you have SS of 3 and want to have a 1 pixel threshold in your rendering the threshold needs to be set to 3 too!

Thanks for you help people. I never expected such prompt and knowledgeable responses

You are welcome
If somebody asks question and support these by example pictures these deserves some response!

[CADMonkey]

Thanks Zom-B,

Learning so much from both of your posts...

With regard to your Curvature suggestion;

Attached is what happens if I increase the threshold to 0.1...

I can see the benefits as triangles are vastly reduced but the inconsistancy increases. On my model anyway.

I have been reading a thread where someone did lots of tests on a brickwork column.

http://www.indigorenderer.com/forum/vie ... w=previous

He used negative values....Could this help?

[Zom-B]

give some values between 0.1 and 0.0 a chance... like 0.05

[CADMonkey]

hmmm. I get your logic but it doesn't seem to allow more than one decimal place.

[Zom-B]

hmmm. I get your logic but it doesn't seem to allow more than one decimal place.

uhh... that seems to be a Skindigo limitation that shouldn't be there -.-'

[Pibuz]

..that is what I was suspecting..
SkIndigo lacks some minor fundamental adjustments. Sometimes they're superfluous, it's true, and that is why they've been reduced, aiming to a easier way of use. Sometimes, instead, they become necessary and there should be a way to control some parameters in a more accurate way (with additional panels and stuff). I've discussed this with Dale already and he's working on that.