Photo real rendering help.

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  07 July 2005
Photo real rendering help.

I'm new to Mental Ray. I've been reading up on it and I've seen some really nice photo real renders. I'm trying to make my soda can here look as real as possible, but I can't seem to get it right. Any help would be appreciated. Thanks!

This is just a scanline render.
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  07 July 2005
Have you given it an environment to reflect? That'll be one of the most important things in a render like this (imo). Right now I can't tell if what I'm seeing near the edges is the edge of a shadow, or a reflection. You may also want to use fresnel reflections, to try and get highlights on the edges. You need a good environment for the reflections because that will help draw the reflections out some more without making the object overly reflective.
Also, since you've chosen such a light color for the design of your cans, maybe a pure white ground plane isn't the best pick? It makes the scene feel kind of flat.
Maybe reposition the camera, and adjust its FOV, as well. The current perspective is kind of odd, with the obvious outward angles in the two outer cans.
The shadows also need some attention, if you're going for photorealism. They seem pretty flat, although the edges are pretty soft. As light and soft as those shadows are, I'd expect to see a much greater falloff in the shadows (shadows getting smaller and softer as they get further from the objects). It also feels like you need a stronger shadow at the base of the cans to help ground them, but a darker area shadow would probably fix that.
I know you're probably wanting to focus on the material, but all of these elements are important for giving it that photorealistic feel.
 
  07 July 2005
Hey Thany!!! Wow, never thought I'd be helping YOU out! Your DSG drawings are always so top notch. Anyways...

So your doing soda cans... good choice, because they are shiny and reflective. This is something that is quite easy to do in 3d realistically.

The first thing you want to do is have the soda cans reflect something. Since you've got nothing else in your scene this can be done with an enviornment map. HDR images (High Dynamic Range) are the best for this purpose. In fact you can often get realistic looking images just by using HDR reflection maps and the scanline renderer. Ummm take a look at this image I used as an example for one of my classes.
This is rendered with scanline renderer and it only took about 2 seconds to render. So for your soda cans you diffinitely want to look into this. You can download some HDR images free from the internet. You can also find a ton of them on this forum.

The next thing you might want to try is using HDRI. The I is illumination. For this you will have to use MR, Vray, Brazil, finalRender, etc. All of them have tutorials on this. You might also want to read up on Global Illumination and Photon Mapping. MR is kind of slow at this, but the quality is pretty good. If you can't find what your looking for just private msg me or something. I always love helping a fellow DSG member.

For the final touch, yeah the try FOV. But I got to warn you... its going to be really really slow.
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  07 July 2005
Talking

Can you used to HDR in scanline?Why I don't know?wow
I surprise to 3dsmax.In face I like better maya more the 3dsmax.
 
  07 July 2005
Originally Posted by chenxuan: Can you used to HDR in scanline?Why I don't know?wow
I surprise to 3dsmax.In face I like better maya more the 3dsmax.

Yes, you can. You just have to enable the light tracer in the advanced lighting tab (and tweak settings, of course).

Quote: For the final touch, yeah the try FOV. But I got to warn you... its going to be really really slow.

I think someone is getting FOV mixed up with DOF...
 
  07 July 2005
Thanks guys, all the info was really helpful.

Here's what I got. I kinda cheated with Photoshop because the original render made my texture look a little washed out.

I used the scanline render I made above and superimposed it on top of the new image. I had a different lighting setup for the new image, that explains why the shadows are going in two different directions. I just set the layer to multiply and lowered the opacity a bit.



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  07 July 2005
Quote: I think someone is getting FOV mixed up with DOF
Yeah oops!
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  07 July 2005
Quote: I kinda cheated with Photoshop


This is not possible! Whatever it takes to get the job done.
 
  07 July 2005
for something so simple and the DOF here I would use photoshop. If you've never used it, learn the lens blur along with a depth map. Create an antialiased one yourself, not the automatically created one max creates. It's not that hot.

Photoreal though; it's usually only as real as the worst part.
The proportions of the can look fine, but the tab doesn't look right. Is that not a US can? If it's suppose to be a US can then I would remodel the tab, Then try and make a better rendering. Fix the biggest thing that gives away the fact that it isn't real First. Keep doing that until there isn't anything left. (never happens, but you get close)
 
  07 July 2005
I think the biggest thing you're missing is the actual aluminum texture of the can. The renders look great, but cans shouldn't be that glossy. Your best bet would be to find some aluminum objects and use them as references for texturing.

If you look at these images:




I found these at http://images.google.com. You can find more examples there. Anyway, if you look closely, there's a brushed/scraped look to the aluminum. Now, when you move down to the labeling, most the labeling can usually hide the scraped look from far away. but it will still be minimally visible when you look at a can close-up. So, the parts that haven't been painted should not be as shiny as the part of the can that's labeled.

As for the label itself, you might want to take it and make it into a hi-res image, then run it through a Photoshop filter like Color Halftone, and then size it down. It's basically the same method the companies use for making their can's labels, as less tones make for cheaper printing costs. Or something like that. Anyway, if you look close at most pop can labels, you can see how speckled it is.

And for reflections, I'd recommend having the reflections blurred/streaked in a manner similar to how aluminum reflects. The reflections can be a lot more clear on the label part, especially with the way companies seem to make the labels a lot shinier on cans these days. But for stuff like the top and the bottom, I'd definitely soften the reflections a lot.

The best way to do this--I did this myself before I replied to the thread--would be to just find a can, and take it somewhere with some light, and hold it up and watch how the various parts of it reflect the surrounding environment, including orientation.

That's about the best advice an amateur like myself can give. Hope some of it helps.
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Last edited by kabojnk : 07 July 2005 at 11:15 PM.
 
  07 July 2005
Thanks everyone.

This was originally a simple setup to help me work on lighting up a scene, so it wasn't too big a deal that I modeled everything accurately. I wasn't even going to model the tab but I decided I should since it just looked funny without one. I know the tab doesn't look real. I just made a box, made two holes in it and applied a mesh smooth modifier to it, and then I adjusted what vertices were there. After I saw my scanline render, I decided to find out how people made those awesome photorealistic images. I spent all day trying to understand MR, but it was real tough, that's why I posted this here. Maybe later on I'll try again when I want to make a replica of a real soda can.


The textures were only 512 by 512 and I did add a brush metal texture to the top of the can, unfortunately you can't see it. The can is definitely too glossy looking right now but I don't know how to fix it since it's using an HDR image as a reflection. I'm new to this whole 3D thing so I'm pretty lost most of the time. The only reason I was able to use an HDR image was because AtmaWeapon sent me a little tutorial he put together via email. Thanks man!


kabojnk: Wow! That labeling idea sounds awesome. I'll try that next time.


All of the info is really helpful; I just don't know how to apply it to what I'm doing in Max. I do feel like I've learned a lot though. I'm just going to take little steps at a time.


I'm pretty much done with this as it is, I'm probably going to do some animation with it and call it good.


Thanks again!
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  07 July 2005
Originally Posted by Thany: kabojnk: Wow! That labeling idea sounds awesome. I'll try that next time.


Aye, I stumbled upon it looking at a can before I replied. I immediately went into Photoshop knowing there was some kind of filter for that kind of thing... unfortunately, it doesn't seem you can really tweak the size of the tone dots to a smaller size than 4 pixels, so I guess the only workaround is to make a realllllly big label, apply the filter, and then size it down by about 25%.
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  07 July 2005
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