Messages

1

[C4D] I need help! / Dark Materials / PBR Reflectivity

« on: 2020-08-26, 18:13:55 »

If I understand it correctly for a simple pbr workflow I am never to change the reflectivity of a material (always keeping it at 1.0 / full white except metals and liquids and such) and simply change the glossiness value / map. I am always struggeling to eyeball and set the correct values at this pointhere and now I have a situation with some dark materials where I completely fail to get a satisfying result.



In my recent example I have two very dark materials: There are the wooden benches on the left that should be stained black and there are the concrete floor tiles. Concentrating on the floor: If too much light is reflected normally I would just use a much lower value for the glossiness (here 0.1) which in a way works.



But if I compare real life images of a similar dark floor (concrete tiles like this are usually more polished) then the value should be around 0.60 to 0.70 I would say.



But the texture stays greyish and washed out + overblown.



The same counts for the wood more or less. It just doesn't look like black wood. So how do I takle this without changing the reflectivity or use a fresnel map in this slot? Am I making a mistake in setting it up or are these correct results under these circumstances of lighting and all? Any help appreciated.

2

[C4D] I need help! / Re: UVW randomizer & procedurals

« on: 2020-08-23, 18:20:29 »

Now, sorry for the delay. Yes, the solution is setting the mapping space within the noise shade to UV(2D), thank you maru. Actually I thought of this before, but as stated above the wood shader does not have an option for setting the space and I didn't think of checking it with the noise shader.

So my understanding now: With procedurals that have the option to set its mapping space the randomizer works, with others (like the wood shader) this is not possible.

Edit: Of course this kills a great part of the usefulness of a procedural shader that should work in 3D and usually doesn't need uv-mapping. Since you can manually change the UV-values manually also with 3d-procedurals, I don't quite understand why the randomizer isn't influencing these settings but I guess that's the way it is for now.

3

[C4D] I need help! / Re: UVW randomizer & procedurals

« on: 2020-08-21, 16:52:31 »

Nope, not the solution I fear. Tried again the setting for "objects" (which I believe would be the correct way when working with one material on a cloner of multiple objects), did not work. Tried also again the setting for different object buffer IDs, this time with a noise shader, no success either, see image attached.

By the way, this test was done on my mac where I still run rc1.

4

[C4D] I need help! / UVW randomizer & procedurals

« on: 2020-08-21, 14:16:18 »

Hey there,

I'm stuck with the randomizer and some wood procedural shader. The help desk article specifically states that procedurals should work, but not for me.

Following the helpdesk descriptions I tried severel different setups (with a group of cubes 3x3x3):

- one primitive in a cloner (setting "objects")
- multiple primitives in a cloner (setting "objects")
- multiple primitives simply grouped  (setting "objects")
- multiple materials with different names  (setting "material name")
- multiple materials with different ID (setting "material ID")
- different object buffer tags (setting "objects ID")
- changing the materials mapping from UVW to box
- changed shader from wood to noise (same result)

but the only difference I manage to generate would be the wood structure stretching over the whole group of cubes or over each object individually. I add two exemplary images to clarify.

Now I hope I'm overlooking some simple setting somewhere or else I assume the procedurals do not work as they should. Just to make sure I am not completly off I also tried a bitmap texture which instantly worked fine.

Any help appreciated.

Working on windows, c4d R17, Corona 6 rc2.

5

[C4D] Bug Reporting / Re: Propagating Mask not working

« on: 2020-08-06, 17:46:26 »

Thanks for the quick reply, sadly that option isn't working for me, neither "always" nor "always without scattering". There is simply no change in the masks between any of the possible selections.

I am still running on RC1 so maybe RC2 will resolv this, I ll give it a try.

6

[C4D] Bug Reporting / Propagating Mask not working

« on: 2020-08-06, 16:52:39 »

Hi there,

for some reason I cannot disable transparent objects / glass materials for masks. I tried all the options under "propagate mask" for the glass material but it doesn't change anything. The older "visible in masks" checkbox is gone, so I assumed this should be the correct place to adjust the setting, no?

Thank you in advance.

Ben

7

[C4D] Resolved Bugs / c4d shaders and bump

« on: 2019-06-04, 23:39:58 »

Hello everyone,

I stumbled across two problems while experimenting with corona bump materials and c4d functions:

1 - As soon as I use the layer shader (not corona layer material) the c4d procedural noise shaders stop working. A single noise works when directly placed into the bump slot, but blending seems to switch it off. I found similar topics concerning this where it was stated that it got fixed (I am running on 4.0 daily May 27). I tried different combination within the layer shader (changing blending modes, using projector) but without success so far.

2 - When using different c4d procedural shaders like wood/marble/checkerboard ... (i.e. not noise) the bump doesn't work at all, not even directly within the bump slot. Aren't these supported?

Interestingly both problems vanish when using the shader as displacement, so only bump seems to get lost.

I hope I did't overlook any obvious reasons for it to not work and I am sorry if this has been discussed before, but like I said, different topics brought no solution for me or tackled slightly different problems with bump mapping. I would appreciate any help with this.

8

Gallery / Re: Koshino House - Tadao ANDO

« on: 2018-12-06, 12:11:05 »

Hey there,

also a bit late but I really like your images! Especially the interiors are super moody, quite excessive actually but still, I find it fits in this case. Except maybe in the last image, that tilt shift gives a bit of a miniature feeling, this is a step too far for my taste. May I ask, how did you create this greenish mood, is it post, LUT?

Anyways, cool images!

9

[C4D] General Discussion / Re: Output Z-Depth sRGB?

« on: 2018-10-19, 09:48:49 »

Ah thank you. I saw the other post but I thought there might be some difference for he was working with his MARI textures. But yes, it affects value driven shaders (in my case displacement, in his glossiness) and the inverse gamma value corrects it, sorry for creating new topic.

While at it I will also test my normal maps as I render these out the same way, let's see what happens there. Thanks for your efforts.

10

[C4D] General Discussion / Output Z-Depth sRGB?

« on: 2018-10-18, 23:34:55 »

Hello everybody,

I encountered some strange behavior with the Output of the zDepth-Channel of Coronas Multipass. To start at the beginning:

I read an article about When to NOT Linearize Your Textures by Mike Boers. I tried to rebuild his setup in a similar manner with the only difference, that I rendered my greyscale-map through the zdepth-channel, the setup looked like this:



The flying planes range from 0 to 100 cm in height. The resulting map I wanted to use for the displacement looked like this:



So far so good. Now I did some testing: I tried to displace a flat plane of same size with this map (EXR) and the bitmap-loader. No matter what setting in the input (embedded, linear, sRGB), the result was always like this:



I would have expected this kind of curve if I told corona to override my linear EXR with 2.2 gamma (if doing this now the curves becomes even steeper of course). The only way to correct the gradient to a correct (linear) stepping was to use an override gamma value of 0.45. So I thought there must be something wrong with the output and in fact, when I color pick the different values of my 32-bit EXR in photoshop they do not represent my intended linear 10%-stepping:



I was sure that the EXR output from corona would be linear, even for the multipass channels. To complete my confusion I then noticed, that when color picking in the VFB it is giving exact linear values after all!



Is there someone who could explain to me why this transition is happening? The background to these experiments is that I usually create my displacement maps by simply rendering them from modeled geometry (since c4d texture baking is not working with corona as far as I know). Do I have to override the gamma value by 0.45 from now on or is there another way?

Just for displaying purposes the comparison of the 10%-step-gradients in linear and sRGB next to each other.

11

[C4D] General Discussion / LWF - Once more with love

« on: 2018-10-13, 15:53:48 »

Hello everybody, I finally decided to join you folks in this amazing forum. Through all these posts, studies, explanations etc. I learned a lot during the past year and first of all I wanted to thank the corona team and everybody else on the forums for their work. Never had that much fun with rendering like I am having with corona (and I am glad that it is still freely accessible for cinema, as I am counting myself to the more hobbyist group of users).

But enough of the flattery. The hard part is that my first question is concerning the good old subject of LWF and color management. Yes, again, another fool trying to understand this whole subject with limited success. I really tried and read a lot, but still some questions remain. I think I understood the basics behind everything, that corona is computing in linear space, but that we need the gamma correction to visualize the colors on screen etc., but there are so many articles and statements about how to use the LWF correctly, reaching back over years, mainly concerning 3ds (which seems to work differently than cinema in setup) that I have to get rid of some confusion resulting from all this mixed up information.

So, what I did was creating two monochrome photoshop images. The first one is a simple square in mid-grey, with a linear RGB value of 0,5 in 32 bit with a 1.0-gamma-profile, saving it as openEXR. From my understanding this should be a perfect mid-grey linear bitmap.

For the second image I converted the first one to sRGB, visually resulting in the same mid-grey square with an RGB value of 188/188/188 and a brightness of 74%, saved as 16 bit in tif-format.

Both were saved with their color profile embedded.

I then created a small test scene in cinema, where I would render a square with these two bitmaps using only the diffuse channel. I used the corona bitmap loader and left the input on „embedded“.

The resulting two images (saved as 32 bit openEXR) were then again opened in photoshop to color pick the resulting pixels. Altogether everything went as expected, the 32bit EXR is identical to the starting image. The second EXR (of course now also 32bit) is slightly off having linear RGB values of 0,5083 respectively sRGB value of 130/130/130 and a brightness of 51%.

Now my questions:

Do these steps describe a correct linear workflow? Since this is my understanding of LWF I just want to make sure …
The slight deviation comes from an interpolation between the 256 from sRGB and the wider spectrum in linear RGB, correct?
Now that both ways appear to have a more or less identical result, do I have to bother with LWF at all? Is this outdated since all sRGB-images are corrected internally to gamma 1.0 by corona?

I guess my problem is (assuming that I understood what LWF means in general) that I don’t know how this effects my images, as the results look the same, at least in this small experiment.

I read about Bertrand Benoit using 180 RGB for his white wall paint in his „classical“ images. In his secret little hideout Dubcat explained this September that Bertrand meant 180 linear RGB with a reflectance (brightness?) of 70.6% because 180 sRGB would have a reflectance of only 46.5% and therefore would be too dark. This I simply don't understand: When I create a square in Photoshop in color space sRGB and fill it with 180 grey, the brightness value is 70.6%, if I do this in linear RGB the values are the same, but of course the color changes. This confused me a lot and brought me to my longterm goal, to finally understand LWF.

Sorry for the long post, I know this has been discussed to the limit, but to be honest I am frustrated about my own confusion and I feel this has to be understood before continuing with things like PBR. Thank you in advance.