Crisper looking light

[yourfather]

Hi all,

 

This is not about chamfer edges or "rounded corners"

 

Im at work and away from my computer so i can't upload an actual sample, but i illustrated an example for you. Please see attached.

 

What i would like to know is, how to i achieve crisper, renders? The light looks flat. See how in the sample the geometry edges have catch light highlights EVEN IN THE LOW LIGHT AREAS? Thats what I'm looking for.

 

Please note:

1. I am using daylight system

2. Yes all geometry either has chamfered edges or "rounded corners" is being used.

3. I get edge highlights just fine if the object is in direct light but i would like even the geometry in the ambient areas to get at least just a little bit

4. I have been faking this in photoshop by sharpening the images.

5. i know about contrast in the exposure control but that ruins the subtleties of the ambient lighting.

 

could it be my final gather or gi options?

 

Edited December 12, 2013 by yourfather

[RyderSK]

Detailed GI definitely does help a lot. Since this is MentalRay, I would say pure FG (not FG+Photons) would yield better result, I don't use MentalRay anymore though, so, I am not knowledgeable much.

The highlight in dim light will still get picked-up if the material is reflective, and every material is reflective to some degree. So I would try that.

[yourfather]

hhhmm,

 

all the solutions about photo real light say to use GI in conjunction with FG. Maybe your first sentence is the key, more detailed GI.

My materials have some reflection too.

 

Anybody know the best setting for more detailed GI? I think it could be the sampling radius.

[RyderSK]

You might as well try iRay with all the scene setup in Mental and see if that gives you the detail/accuracy in shadow/highlights. If yes, than you will know it's just matter of GI.

[yourfather]

yeah iRay never ends up looking good for me and of course it just keeps going on so i have no idea how long its going to take to get a realistic result. I will check to see if it works with my materials and lights as i know its a little limited when it comes to that.

 

Thanks again Juraj.

[Francisco Penaloza]

For better light, you need high values in Final Gather, if you are using the latest version of 3DsMax the new IBL with Final gather work very well and pretty accurate. if Studio shot is what you are aiming for, you are better off using area lights or portal sky, that with a good combination of Final Gather should be enough to create high end result,

to Sharp your image you need to adjust your antialising too.

For quality in Final gather you have Bounces, Initial point of density, Rays per FG points and interpolation

increase bounces until your scene is well lit, then increase your rays to have cleaner GI(no photon mapping) interpolation will help you to erase splotched, but to high values loses details. and very important is the initial point of density values close to 1 or ever more will increase the detail in your GI. but be careful to high values will trow your render time to the roof.

and don't forget of shadow samples too, in the IBL roll out and for each light.

 

Photon mapping is a good method to get a rough GI in poor lit situations or many objects in your scene, but you get more details from Final Gather, now as mentioned before with the latest releases of 3DsMax final gather is strong enough to work by it self.

[yourfather]

I will really look into this.

 

However, FG never bounces light like GI. Thats why I'm using GI and photon mapping then using FG to smooth out the low photon count (200,000 per light portal and sun).

 

I will turn of the GI but theres hardly any light bounce. I thought FG and GI together were suppose to be excellent for nice light bounce.

[Justin Hunt]

one key to getting good detail with GI is to use a lot of small radius samples, rather than larger radius/fewer samples.

 

Dont be afraid to shoot a few million photons with a sample radius around 50 to 100mm. Photons are cheap use them. Also increase the trace depth to at least 100 with the reflection and refraction depths of 50. Let those photons bounce around.

[Francisco Penaloza]

Don't take me wrong, Photon mapping it is a very valid method to calculate GI, and the optimum way to use it is with FG, from my point of view is when less variables the better, I always approach a scene first only with FG, if after trying my magic on it, it does not work, then I add Photon mapping and re adjust everything, the "problem" is Photon mapping is a very old method to calculate GI, and it need very high values to be precise, that's way Mental Ray add Final Gather. Now years pass by and even Final Gather method is kind of old, Irradiance mapping in way more efficient, and so are new methods such path tracing and so on.

So if you want to use Photon Mapping and Final Gather, things to consider are, Photon radius, number of photons per samples and Average Photons per lights.

When smaller the radius the more defined solution, but you'll need more photones per samples and way more photons per lights. 200000 it is rather low amount, complex scenes can go over millions of photons, and this is fine, because they are calculated only once, then no matter where you are in the scene you can save and use the same solution, this is one of the advantages of photon mapping.

Now since you are looking for fine detail in shadows and soft shadows, then area lights, portal light and Final Gather should be your first option, then if your scene is not well lit then add photon mapping to it. After a few test you'll find out right away if FG will do or not.

Density of 1 or 2, Rays of 200 or more and interpolation of 80 more or less depending of how many rays will get you a clean image. of course your scene will vary depending of your light sources.

[Justin Hunt]

I mean GI with FG, not just GI only which will wont give a good result.

 

High density FG can take for ever to render, often too long for adequate results, so dont go too dense.

[yourfather]

I know what you mean Justin.

 

Your first post was exactly what i was looking for. When i get home I'm going to try every bodies suggestions and see the difference. I am also going to upload my FG and GI settings.

 

Thank you all.

[Justin Hunt]

I wrote a blog post a while ago which outlines my typical GI FG setup I used for interiors. Its a little dated but hopefully still relevant http://justinhuntvisualization.blogspot.com.au/2011/09/tutorial-templestowe-sitting-room.html