Yafaray x Kerkhytea

[micheus]

This thread is intended to help people like me - without any experience with Yafaray - to understand how to set for yafaray some materials we are used to get it easy in Kerkythea.

Here is the simple scene I was using for my tests (without no luck):


Bellow is the look I was first looking for. I rendered it in Kerkythea with not much effort.

Render method: PhotonMap-High AA 0.3
Wall material: Matte/Phong
Star material (tweaked in KT):
#1Matte/Phong (white Diffuse)
#2Dielectric/Glass (white Reflection/IOR 1.6/Fresnel)
#3Matte/Phong (red Specular/Spec.Attenuation Fresnel/Shininess 15.0/Spec. Sampling)
Point Lights (Omni) with Soft Shadows activated with a radius of 1.2.

Bellow are the results I can get just varying the render method.
The materials are the Shine Diffuse
Point Light#1: Power 100%
Point Light#2: Power 85%
Point Light#3: Power 85%

DirectLight

PhotonMap GI

PathTracing

Bidirectional PathTracing

SPPM

---

So, I couldn't get a good enlighten scene without "extrapolation" the light power as well I couldn't get the star shinning.

I hope this can help us to start the proposed discussion.
Thanks

[oort]

Micheus,
Thanks for starting this topic. It might help others who may want to give YafaRay a try...

I do not know if Kerkythea requires a box around the entire scene but for YafaRay you do not have to have that. As a matter of fact, I have only rendered one scene with a closed off area and that one had a window in it. That may be what is making it difficult for you to get a good render.

Also I have not played with point lights very much. I am lazy and usually just use an Ambient Light with an HDRI with Enlight enabled. Sometimes I use spot lights and area lights but point lights almost never...
I need to spend some time playing with point lights...

If you remove two sides and the top of the box you should get better lighting. I do not have much time today but will spend some time on this on Monday.

Edit: The advantage you have with exporting to KT and rendering in it, is that you have access to a library of materials. If we can get more Wings3D users using Yafaray, we could start sharing settings by sharing Wings3D files containing materials like gold, silver, glass, etc. I had created some files like that for old Yafray but have not converted those to YafaRay yet.

oort

[micheus]

I started without the box (light enclosure) but as the result wasn't good I ended up using it hopping I could get what I was looking for. I also had stated using a glass material that works better in closed spaces since it can reflect the walls, floor,...

[oort]

If you have an HDRI (I use the kitchen probe most of the time) in the Ambient light that will reflect on a glass material. Just make sure that Transparent Refraction is turned off in the Render settings.

I think that YafaRay is pickier about your model than KT is. I will e-mail you a modified version of your file. Notice the strangeness in parts of the glass model.

You will need to download the kitchen probe hdri file from the link to HDRI files that is on my website. Then modify the Ambient light in the wings file to specify the location of the HDRI.

Sorry I do not have more time tonight.

oort

[micheus]

I have a lot of HDRI (I linked them in a post in the Useful Repositories thread).
But, I tend to not used them. I want the idea to play with light settings as in the "old school"(?).

Notice the strangeness in parts of the glass model.

That was I something that make me gave up of the glass material and try the most basic one.

I changed colour composition for the star for get a better visualization for the transparency/refractions/reflections.
Then, I played with the Subdivision and Raydepth parameters in the Render Option dialog. We can notice as greater we set raydepth worst the result become and as more subdivision we add better it become:

* See the full resolution image

After that I checked the results for the default Raydepth value (12) and I set Subdivided to 0, 1, 2 and 3. But, - in terms of differences - in the final image we cannot see much improvement after the value of 2. (the strangeness is still there).
I also create a high resolution model that should generate more uniform shapes during the triangulation process by yafaray, but it doesn't produced any relevant difference (some spots just changed its place):

* See the full resolution image

Well, it seems to be have to get a good result - using the Glass material - if we are working with a complex object.
The strangeness is the result of the internal reflection/refraction of the shining bevels - the white spots are the same we see in those areas.
The AA default values are the usual for most renders, but I couldn't get a good result for any kind of method offered by yafaray.

All the project files can be found here.

[oort]

Micheus,
I have been trying to find a setting to get rid of the noise (strangeness/lines) in parts of the glass. It seems to be related to the Autosmooth angle setting in the material properties object parameters. Setting the angle to 180 or 0 seems to give better results. I have not been able to remove all of the noise yet. Maybe this is something that needs to be fixed in YafaRay. I am going to keep looking for a solution.

Thanks,
oort

[micheus]

It seems to be related to the Autosmooth angle setting in the material properties object parameters.

That has passed to my mind when I was coming home this morning. So, it's something I will not need to check. Thanks.

I also had concluded this must be a kind of "bug" in Yafaray. As well as I think the AA has some problem too.

[oort]

Micheus,
I finally found the following.. Smooth/Solid Poblem

I tried to set all the edges in your model to hard edges. For some reason I am having trouble doing that.

Not sure if that is the cause of the lines or not???

oort

[oort]

Micheus,
I think that YafaRay does not like the way the model is created. For a test create a cube and use shell extrude to add sections to the model. Make sure that Autosmooth is set to 180 or other high number. The test model will render ok... I think...

oort