Even more lighting issues

Cat_Dancing

I would very much appreciate comment on the attached images please. The pre-render image is good and well lit and I am very pleased with it, however my rendered image lacks light and the brass colour of the trumpet has changed to black. Bizarre. I have tried everything in the book to get decent lighting, watched videos, read posts and other written comment, tried HDRI and all sorts of different settings within DAZ. My best efforts seem to always be when I use a photograph as a background such as the attaced desert scene. I would so welcome all comment, advice, observations, tips & tricks, whatever you've got, just bring it on please. Not difficult to differentiate between rendered and pre-rendered.

Thanks for your time.

Richard Haseltine

Metal will appear black if theer is nothing for it to reflect - the prview used doesn't do ray-tracing so it shows the cclour assigned. In general, think about how you want the scene lit and use that to guide your placement of lights - of course you may well nto want truly realistic lighting with toon figures anyway.

kenshaw011267

For your lighting issue (i think you have some other issues)

in the render change the HDRI to one of a bright day. The one you're using isn't very bright. Also since you're using it as the background use a higher res image (8k rather than 4k probably).

Cat_Dancing

Richard Haseltine said:

Metal will appear black if theer is nothing for it to reflect - the prview used doesn't do ray-tracing so it shows the cclour assigned. In general, think about how you want the scene lit and use that to guide your placement of lights - of course you may well nto want truly realistic lighting with toon figures anyway.

Hello Richard, thank you for reponding. Not sure about your first comment, how do I provide something for the trumpet to reflect? I though I had done that by providing lighting. How do I make the previwe 'make ray-tracing? The preview is how I eant it to be lit I used two of the white cubes provided under 'Lights' Outdoor Lighting 200% Intensity. What am I doing that makes my renders so darkened?

Thank you as always for your support.

 

 

Cat_Dancing

kenshaw011267 said:

For your lighting issue (i think you have some other issues)

in the render change the HDRI to one of a bright day. The one you're using isn't very bright. Also since you're using it as the background use a higher res image (8k rather than 4k probably).

Hello Kenshaw, thank you for your comments. I've had very little success with HDRIs, I've had dificulty with importing them and then making them work for me. How do I 'Use a higher res image'. You are correct I do have other issues, could you please point them out, maybe offer a solution. I've watched so many tutorials my eyes are now square.

Have a nice day.

 

fastbike1

@Cat_Dancing "I've had very little success with HDRIs, I've had dificulty with importing them"

You don't need to import a HDRI image. Just save the .hdr file (the place you get them from will have the resolution). Insert the selected .hdr file in Render Settings>Environmentl>Environmental Map. Click the drop down arrow on the slide and browse to your .hdr file.

The HDRI files are typically offered in a verity og resolutions. I typically use 8K maps. You want to look for maps that advertise a reasonable number of "stops" of exposure. I suggest at least 10 stops. More is generally better. 

Cat_Dancing

Hello Fastbike.

You Sir? are an absolute star. I've answered straight away out of politeness but will absorb your comment in depth later. In the meantime I am in the same dilemma as you with regard to HDRI,I just don't seem to be able to get it, I've spent days trying tolearn it and get it right. Here's my latest (Att) effort with my Toy Town Army scene. I've totally overdone the lighting, the final reneder is better but, disaster, I still have a black trumpet and I really haven't a scooby-doo how to correct the problem.

Gordig

To help illustrate the importance of HDRI resolution, here are some renders I made for another thread, using the exact same HDRI from HDRIHaven at four different resolutions:

1K:

2K:

4K:

8K:

It's also important to consider that an HDRI is a spherical image of which you are only ever seeing a portion, so an 8K HDRI doesn't result in an 8K background, but probably more like 2K (not going to do the math on that).

Cat_Dancing

Great llustrations Gordig well done, if only I could do it your way. As I've written earlier in this forum post, I just don't seem to get it, why? I don't know. I have looked at countless video explaning both light and HDRI but when I put it into practice it fails. 

Thank you for trying to help.

Gordig

Let's try something here: hide everything in your scene except the main figure (including the lights), and then render. I see an HDRI, but also a backdrop; is that a piece of geometry in the scene, or just a backdrop in the scene tab? Where are your tonemapping settings?

kenshaw011267

Ok. Time to get this down to absolute basics.

HDRI is High Dynamic Range Image. What it really means for us is a three dimensional dome shaped image with lighting built in. If the scene is outside you generally don't need any other lighting. iRay will reflect it very nicely.

To use an HDRI strictly for lighting just follow the directions @fastbike1 provided. If you also want it to be the background of your render also turn draw dome on (the button you can see in render settings in the image he provided).

This is for iRay of course. 

What isn't working for you? What happens when you try it?

fastbike1

@Cat_Dancing  "In the meantime I am in the same dilemma as you with regard to HDRI"

?? I don't have any dilemma with HDRI. I use an HDRI in virtually every image I render.

To expand on @kenshaw011267's post above (and my previous), the resolution of the HDRI matters only if you want to show the background iamge (i.e. Draw Dome: On). The number of exposure stops always matters since this is the range of lighting values included in the HDRI.

Your Trumpeter image looks fine. The trumpet is black because the HDRI is so diffuse that the light doesn't reflect strongly on the trumpet (@Richard Haseltine's post). In this case you can add a spotlight focused on the trumpet. Dont' despair, there are a lot of parameters that can be adjusted with Iray and HDRI. If the lighting angle isn't what you want, you can rotate the dome, but thats a bit of trial and error to get the rotation you want. I make small renders for that so that I can get quick results. You can also increase or decrease the Environment Map slide for more or less light,

Hylas

I don't see how the lighting in this image is "overdone" and a "disaster"? What do you not like about it?

 

As for the trumpet, I suspect it has a 3DL shader applied to it instead of IRAY.

Select the trumpet, go to Surfaces, and apply IRAY Uber Base.

Then set Metallicity to 1 and Glossy Roughness to about 0.1 to 0.2.

(Or take a shortcut and just apply the IRAY Gold shader.)

Does this help?

Cat_Dancing

Hi Gordig, Please see att pic of tone-mapping. You are right that's a backdrop from a photo found on the internet.

Hi Fastbike. Thanks for your input I will experiment with exposure stops.

Hi Hylas. Ihad to really over do the lighting (see att) in the pre-render to get a decent. I tried select trumpet then surfaces but could find no 'IRAY Uberbase' or 'Metalicity' but I will experiment with all the other settings such as Refraction Color - Reflection Color and Normal Map to seee if I can come up with a solution.

Thank you all for your input.

Gordig

Cat_Dancing said:

You are right that's a backdrop from a photo found on the internet.

That doesn't answer my question.

kenshaw011267

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

Cat_Dancing

Hi Gordig - Still working on it, not sure what you mean by 'is that a piece of geometry in the scene, or just a backdrop in the scene tab?' Thanks for your continued input. (Like your DA page)

OK Kenshaw I will remember your advice, Thank you.

Hylas

kenshaw011267 said:

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

This is not true if you use the "Environment" tab to place the backdrop.

kenshaw011267

Hylas said:

kenshaw011267 said:

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

This is not true if you use the "Environment" tab to place the backdrop.

Yes, it is. Try it yourself. The HDRI lighting from that direction won't cast shadows because it isn't there at all.

Hylas

kenshaw011267 said:

Hylas said:

kenshaw011267 said:

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

This is not true if you use the "Environment" tab to place the backdrop.

Yes, it is. Try it yourself. The HDRI lighting from that direction won't cast shadows because it isn't there at all.

Made two quick renders to demonstrate.

1st render shows a figure crouching on a primitive, lit only by an HDRI. Draw Dome is on.

2nd render is the exact same scene with a JPG dropped into the environment slot. Shadows and lighting stay the same.

Images in the environment slot don't affect the lighting of the scene in any way.

 

Cat_Dancing

kenshaw011267 said:

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

Hi Gordig. Render att of just the main character and nothing else. Have I interpeted your request correctly?

 

Gordig

Yes, although I don't know why you quoted Kenshaw to say that. The figure is more than adequately lit, so I agree with Hylas that it's a shader problem. Select the trumpet, go to the Surfaces pane and select a surface. At the top of the pane, it should say "Shader: _____". If that DOESN'T say "Iray Uber", or something similar, then you need to apply the Uber shader. Go to Default Resources in the Smart Content pane, and with the trumpet selected in the Scene view, and the surface(s) of the trumpet selected in the Surfaces pane, double-click the !Iray Uber Base to apply that shader to the trumpet. Then render.

Cat_Dancing

kenshaw011267 said:

Don't use backdrops with HDRI's. The backdrop will block the light from the direction of the backdrop.

Hi Gordig. Render att of just the main character and nothing else. Have I interpeted your request correctly?

 

Cat_Dancing

Gordig said:

Cat_Dancing said:

You are right that's a backdrop from a photo found on the internet.

That doesn't answer my question.

Hi Gordig. Render att of just the main character and nothing else. Have I interpeted your request correctly?

 

Cat_Dancing

Gordig said:

Yes, although I don't know why you quoted Kenshaw to say that. The figure is more than adequately lit, so I agree with Hylas that it's a shader problem. Select the trumpet, go to the Surfaces pane and select a surface. At the top of the pane, it should say "Shader: _____". If that DOESN'T say "Iray Uber", or something similar, then you need to apply the Uber shader. Go to Default Resources in the Smart Content pane, and with the trumpet selected in the Scene view, and the surface(s) of the trumpet selected in the Surfaces pane, double-click the !Iray Uber Base to apply that shader to the trumpet. Then render.

Thanks for this Gordig. I quoted Kenshaw because I clicked thr wrong button - Sorry.

I will definately follow your instructions this-afternoon and see where it takes me. I'll get back to you tomorrow. Thanks again.

 

Cat_Dancing

Thank you everyone who has conributed to helping me with this. I am well on the way to getting to grips with HDRI and I have solved the problem of the black trumpet. (You have solved)

Thank you all very much indeed.

fastbike1

@Cat_Dancing

Glad you didn't give up and are getting there.