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Greeneagle

HDRI/global illumination in C4D - question from a photographer

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Hello!

 

I am an advertising photographer that is quite new to 3d, but is planning to get good enough to be able to incorporate 3d in my photography.

My understanding is that hdri and global illumination is the way to go to match the lighting and reflections in a real world scene.

 

I am trying to follow this tutorial, but I don't get the same shadows and light color as in the tutorial. I'm using Cinema 4d R11.5, but I had the same problem with R10 and R11 also.

 

 

51.jpghdrisphere.jpg

--------------------------------This is the result in the tutorial ----------------------------------------------------------------------------This is my result----------------------------------------------

 

 

What am I doing wrong? What render settings should I use? When I used R10 with the old GI-engine (like in the tutorial) I had the correct settings, but still got the same result.

I seem to get a soft shadow no matter what I do. I have also tried with my own made hdri maps, but still to soft shadows (hard shadows in real life).

 

Also I am wondering how to export my rendered object(s) with shadows (without the floor object), from cinema 4d to photoshop, using global illumination as lighting. My goal is to put them seamlessly into photos.

 

 

(Sorry my english, I am from Norway;)

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Seamless integration with photo's is really annoying in c4d, i still havnt figured it out completely, you'll have to wait for someone else.

 

As for your images, firstly that tutorial is very very old.

 

All you have to do now is put a sky in and a material with the hdri in the color or luminance channel onto it.

Then play around with the exposure and hdri sliders of the image. ie click on the material, then click on the long bar with the path of the image.

 

cheers

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Thank you for your answer! I have actually tried the new method with the sky + hdr material and playing with the exposure, hdr gamma, black point, white point, -still the same soft shadow..

 

Is anybody able to get the same result as in the tutorial? (Two main shadows, cold and warm light.) You can get the hdri angular map here: http://www.debevec.org/Probes/kitchen_probe.hdr

 

cheers! :)

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It looks like they are using other lights for the shadows, maybe even 2. Try addeing more lights with shadows turned on.

I was just about to say that.

I have never seen shadows that sharp come from HDR lighting... that's not really what it does.

If the shadow is the main thing that's bothering you just add a shadow caster.

 

-m

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I was just about to say that.

I have never seen shadows that sharp come from HDR lighting... that's not really what it does.

If the shadow is the main thing that's bothering you just add a shadow caster.

 

-m

 

Hmm, that sounds a bit strange, who would put lights in a tutorial where the hdri lighting is the whole point? If you look at this hdri tutorial, you can see the same type of shadows being cast.

 

Here:

newhdri_e.jpg

 

Sure I could add some lights to get the shadows, but its not very easy recreating the kind of shadows you see on the image to the right. With my intentions on compositing my 3d objects in photos with "real" shadows, it would help a lot if the hdri lighting would act like in the tutorials.

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nah ignore the people that say add shadow casters =P

 

so far i'm getting close. se ur exposure to -0.47 and ur hdr gamma to 0.96

 

then its a matter of turning up the accuracy of your gi calculations.

 

i can post a scene file if it still doesnt work for you.

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Thank you, that's a bit helpfull. It's definitively getting closer, but I'm still not there yet. I'm pretty sure the shadow would be sharper from the ceiling light.

This is my closest result using your numbers:

hdrisphere2.jpg

Is this the same as you got?

 

Any hdri experts out there? :)

 

Also, does anyone know how to export the sphere to photoshop without the floor, but keeping the shadows? I cant seem to find a good way, using hdri lighting. With normal lights I know it's possible.

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nah ignore the people that say add shadow casters =P

Or listen to Vozzz (the guy who doesn't know that putting an HDR into the color or luminance channels yield entirely different results) and wait 3 more days until you manage to get the right results. :P

 

Some of us have been using HDR lighting since Paul Debevec was the only HDR game in town. MAXON completely rewrote their GI algorithms since that tutorial came out. Are you trying to learn how to use HDR's or are you trying match the image? Are you seeking photometric results? Because AR3 is probably the least like real world lighting compared to VRay, Maxwell, and a host of other renderers. Hell, without DeGamma... results still look fake.

 

It is not uncommon to use actual lights with HDR lighting to get exactly what you are looking for. Whether it works for you in this case or not it's a good lesson to learn. If you would have added a shadow caster you would have been done by now.

 

Now I entreat you to go back to ignoring me.

 

-m

Edited by the_Monkey

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This is a bit of a noob question, but the fact is I'm very new to this 3D, having just picked up C4D a couple months ago. What exactly is HDRI? I know i need it for nice reflections, but I don't know why. Is it something I can produce myself, say from an existing photograph? If anybody would like to shed some light for me, I'd appreciate it.

-j

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HDRI = High Dynamic Range Imagery. A regular 8-bit image has 255 levels of gray, from black to white. An HDR image has as many damn gray levels as you want. Generally, HDRI is used to pack up exponential illumination. The sun is exponentially brighter than a lightbulb which is exponentially brighter than the floor. By encapsulating this super high range of illumination (hence, High Dynamic Range) you can simulate really kickass, complicated lighting without having to actually bounce lights around a whole room. It's not something you can make from an existing photo. To make an HDR image you have to shoot for it, usually by putting your camera on a tripod and shooting the same scene at different exposures/f-stops, then combining them in photoshop into an HDR pic. Oorrrr you can download pre-made ones.

 

Hope that helps.

 

~CTB

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Or listen to Vozzz (the guy who doesn't know that putting an HDR into the color or luminance channels yield entirely different results) and wait 3 more days until you manage to get the right results. :P

 

Some of us have been using HDR lighting since Paul Debevec was the only HDR game in town. MAXON completely rewrote their GI algorithms since that tutorial came out. Are you trying to learn how to use HDR's or are you trying match the image? Are you seeking photometric results? Because AR3 is probably the least like real world lighting compared to VRay, Maxwell, and a host of other renderers. Hell, without DeGamma... results still look fake.

 

It is not uncommon to use actual lights with HDR lighting to get exactly what you are looking for. Whether it works for you in this case or not it's a good lesson to learn. If you would have added a shadow caster you would have been done by now.

 

Now I entreat you to go back to ignoring me.

 

-m

 

I definitively want to learn more about HDR lighting, but I am quite convinced its possible to achieve good result without having to use extra lights. Of course I can add the extra lights, but I still want to have as good starting point as possible.

 

Should I rather start learning other 3d tools with better photorealism renderers than c4d (3dsmax?)? Maybe vray for c4d is a good starting point? My goal is to be able to blend CG in photos as seamlessly as possible, so where should I go from here? Any tips?

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I definitively want to learn more about HDR lighting, but I am quite convinced its possible to achieve good result without having to use extra lights. Of course I can add the extra lights, but I still want to have as good starting point as possible.

You will find that this is usually not the case. Monkey is right. It is very common to use additional lights in a scene incorporating HDRI.

No single piece of software will give you perfect results. There will always be some massaging to get the results you want. I know there are a billion

tutorials out there about using HDRI and a great deal of them simplify its use. One thing HDRI is not is a one-click solution to perfect lighting. Especially

when integrating with other scenes. This is why you see such poor lighting in many reels. They slap on an HDRI an call it a day...

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That's a very good site for hdr imaging, thank you. Does anyone have any good sites/tutorials especially for blending cg with photos?

I still haven't quite figured out how to export my rendered object in to photoshop, with the shadows, but no floor. Is this even possible with global illumination? If not, what is the best approach for doing this?

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Guest Sao_Bento

Or listen to Vozzz (the guy who doesn't know that putting an HDR into the color or luminance channels yield entirely different results) and wait 3 more days until you manage to get the right results. :P

 

Some of us have been using HDR lighting since Paul Debevec was the only HDR game in town. MAXON completely rewrote their GI algorithms since that tutorial came out. Are you trying to learn how to use HDR's or are you trying match the image? Are you seeking photometric results? Because AR3 is probably the least like real world lighting compared to VRay, Maxwell, and a host of other renderers. Hell, without DeGamma... results still look fake.

 

It is not uncommon to use actual lights with HDR lighting to get exactly what you are looking for. Whether it works for you in this case or not it's a good lesson to learn. If you would have added a shadow caster you would have been done by now.

 

Now I entreat you to go back to ignoring me.

 

-m

Wow, this is the first time I've looked at this thread.

Note to Greeneagle - If you pick one guy to listen to regarding Cinema 4D around here, make it the_Monkey.

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@the_monkey: Sorry man, didn't mean to offend you. ( i just gathered that he wanted to achieve the result without using lights)

 

Really? putting it into luminance and color yield different results? is this new to AR3? i havnt used ar3 too much, but it used to be irrelevant if you stick it on a sky object. it just reads the color channel as a luminance channel.

 

 

 

@ everyone else: yeah that's what i got too. I think as mentioned it was because it was a different GI engine when that tutorial was made. it used to produce a lot sharper images.

 

unfortunately that's as far as i can help you.

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http://hdrlabs.com/news/index.php

 

this entire site is a great resource for HDRI. Someone should write a Cinema loader for it if there isn't one already floating around.

 

http://www.hdrlabs.c...w_it_works.html

 

 

There is one floating around, Lumen2. It's a commercial plugin that supports SmartIBL amongst other things.

 

Biomekk.com - Lumen 2

 

Greeneagle,

 

I'm sorry if I'm stating the obvious, but since it wasn't mentioned....Instead of trying to get the perfect result straight out of the renderer, I'd look into multi-pass workflows (Compositing Tag). This is where you'd also use a separate shadow caster & render the shadow as a separate layer (along with your object, floor, GI, etc.) and do the tweaking in Photoshop.

Edited by JakeL

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@Everyone, thanks for your help!

 

There is one floating around, Lumen2. It's a commercial plugin that supports SmartIBL amongst other things.

 

Biomekk.com - Lumen 2

 

Greeneagle,

 

I'm sorry if I'm stating the obvious, but since it wasn't mentioned....Instead of trying to get the perfect result straight out of the renderer, I'd look into multi-pass workflows (Compositing Tag). This is where you'd also use a separate shadow caster & render the shadow as a separate layer (along with your object, floor, GI, etc.) and do the tweaking in Photoshop.

 

@JakeL, Lumen 2 looks interesting, thanks for the heads up!

As I'm no expert in cinema 4d, I haven't gotten the multipassing to work the way I want, when using GI. With standard lights, I have, but not with GI. Do you have any links that could help me with this (especially rendering the shadow as a separate layer)?

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For what it's worth, Greeneagle, I'm also trying to learn how to create rendered objects with alpha shadows for placement into photos.

 

I am currently working with HDRI scenes with cars but my goal is to place rendered furniture into photos of existing locations.

 

Hopefully someone can offer a solution with C4D.

 

fyi - I'm using r11.

 

Anyone?

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@Everyone, thanks for your help!

 

 

 

@JakeL, Lumen 2 looks interesting, thanks for the heads up!

As I'm no expert in cinema 4d, I haven't gotten the multipassing to work the way I want, when using GI. With standard lights, I have, but not with GI. Do you have any links that could help me with this (especially rendering the shadow as a separate layer)?

 

Have you tried multiplying the GI pass with your BG plate?

 

Dan

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