Need tips on rendering

[tac603]

Hello all,

I'm quite new to 3d max. Been learning on my own whenever i have the time. Anyway, you can tell I'm really weak when it comes to rendering. I'm designing some apartment and have done a massing for study (as shown in the pic). I used the Default Scanline rendering thing. The underside of every object is really dark, almost black. I tried using the Advance lighting because there's this 'bounce' option but it takes way too long to render. I've installed VRay but havent a chance to use it yet.

I have seen some really nice renders and they look so real. Can someone give me some tips on how to render it, at least make it look 'more real'. Sorry my english is not good.


Thanx in advance.

[geldslaw]

personally I think you're off to a fantastic start and yes after a while you do feel that scanline is taking to long to render? Thats when you want to and need to move over to mental ray. Vray is an awsom rendering engine as are many others.

after getting to grips with modelling and texturing you do tend to want to upgrade the final results without having to weight hours for your render to finish but it is worthwhile taking the time to decide on which rendering engine to use. You'll have to dedicate some time to doing render tests to get the feel and application of the rendering engine.

In effect its another program completely different and independant of the modelling application and richly deserves the time and effort to learn it. I emphasize this because it has a mulitplied knock on effect. Don't rush it, take your time, better to learn how to use the render engine over 3 days than to spend 3 days on every render trying to correct your rendering mistakes.

Once you have decided on the rendering engine let us know because lots of the members of the community can and have used several different engines but we all have our own personal favourite and will be more than happy to assist you as much as we can to learn how to use the rendering engine you choose to produce the best work possible.

[tac603]

Hi geldslaw, thank you for the reply. I will spend some hours tonight to test render some basic elements. I did go for a few rounds previously but there are just too many settings /jargons when it comes to V-Ray. For example, I get hard shadows from VRay rendering. I am not sure where the settings are to control shadow because the advance shadow perimeters seem to have no effect. For example the Density setting and the colour or it.

On the Default Scanline, I could change the settings easily from the setting rollout. I normally use Area Shadow, and set the sampling to 3 for a smoother shadow. I guess I'll have to spend more time reading lol. Thanx again.

Regards.

[robinmitra1]

as u can see,the model is very complex with so many geometries.and so,scanline render is best to render is fast enough.if u want to go for realism u could composite it in photoshop or u could use some good renderers like vray or mental ray or brazil,etc.but remember gi calculations take a lot of time and gi is the core component of these renderers.so its all upto you to decide upto which level of detail u want to go for,and does it justify the time that is required for test rendering and then final render?

[MrTom]

VRay is a wise choice, and well worth taking the time to learn.

I agree at first the immense amount of settings can seem daunting, but you will soon learn that you need to change very little in order to achieve similar results.

Changing from one render to another is like moving house, everything is still there but just in a different place, and it will take time to familiarize yourself with it.......and getting used to different terminology too! lol.

As already said, a good start with the default renderer, but if you are going to change renderer, and you have VRay, then use it.....why spend all that money on something and then not?

Regards.

[tac603]

Hi Robin & MrTom, thanx for your insights. I am trying out my VRay now. I have a feeling it's gonna look weird lol. All I'm doing is set VRay as default Renderer. Then choose a Direct Light as light source, check the VRay Shadow and some minor tweaks I learned from the internet. I'm still waiting it to render, it's starting the Prepass thing and been almost 15 minutes *oh man*. I'll post the results as soon as i get it done. Hope you can give me some tips later. Thanx !

[tac603]

Just as I expected... I dont know how to describe it.. it's beyond words LOL. Where it went wrong? I had GI turned on.. and both Primary and Secondary bounces were set to 1.0. I suspect I have to decrease one of them ? Please advice.

[MrTom]

Hang on mate.......just getting some stuff together to help ya out........be back in a minute or two.

PS. That looks like my first render in VRay too!

Regards.

[tac603]

Thanx mrtom... I'm experimenting vray while waiting. Please take your time.

Pic 1. I assigned white colour to the box, since my earlier model was white too. Here, all basic settings, especially the primary and secondary bounces, both set to 1.0


Pic 2. I've tuned down the settings, primary being 0.8 and secondary being 0.5 (Funny tho, the box looks a bit greenish. Reflection from the green plane surface?) But if you notice the top horizontal plane of the box, it appears really bright

Pic 3. I replaced the Direct Light with an Omni. Looks smoother, especially the shadows. I think the shadows are only adjustable at the sidebar under VRayShadows params ?

[MrTom]

Ok, first off that's just the sort of result I would have expected too...lol, I should have pointed out one or two things earlier...sorry.

Now this may seem complicated, but in fact it's not. Yes there are an immense amount options but only a few need to be changed to start with. Why doesn't it work from out the box? Well it's default values are for a high quality render, not only that, but VRay is also optimized for using VRay materials and lights.....yes you can use standard materials and lights but the time taken to render them will be longer.....it's very much a balancing game i'm afraid.

So, some settings to get you going: (well the ones I use at least)

In the Render Scene Window (F10)

Common:

You can leave this at the default....maybe change the 'Output size' but that's all.


Renderer:

Global Switches:


Turn OFF the default lighting.......this is used in case you don't have any lights in your scene.


Image Sampler:


Type:

Fixed. Good for detail. Not so good for large areas of single colour.
Adaptive Subdivision. Good for large areas of colour. Not so good for details.
Adaptive QMC. Good for both....an allrounder.

Antialiasing filter:

Different ones gives different results...obviously...'Area' is the default and is fine to start with.....I choose 'Mitchell-Netravli' well, because I like it.


Adaptive Subdivision:


These are very important. You will get a different rollout depending on the sampler you use but generally the greater the difference between these two numbers the higher the quality of the image. You can start at 0,0 and work your way up from there, decreasing the Min value, and increasing the Max value. These are directly related to 'Bucket Size' too which i'll come to soon.


Indirect illumination (GI):


These settings determine the primary and secondary bounces, and how they are computed. Again different ones calculate the GI in different ways. 'Irradiance map' for primary and 'Light Cache' for secondary is fine, Quasi-Monte Carlo takes a little longer but gives much smoother GI....I think anyway.

You'll get another rollout for the Light Cache but default settings are ok to start with.


Irradiance map:


Set the preset to LOW. This will reduce your render time 10 fold. Start with this as a basic test render setting before going on to higher levels.

You can set the HSph. subdivs to 40 without significantly increasing the render time, any higher than this is pointless as the extra time taken to calculate it is not really worth the very small, almost non-existant, increase in quality.

HSph. subdivs=20 is again a good 'test' setting.


rQMC Sampler:


MOST CRITICAL. This value is 0.001 by default. Yeah it's good but will increase render times to beyond belief! Ok we don't want any noise in our rendered scene but there are limits on how long it takes...right? Set this to 0.005 to increase the threshold of noise....yes the scene will be more noisey but not that much that will be visible.....unless you do a real close up render of the object. This setting is good for most renders, 0.002 is better but render times will increase sharply.


Colour mapping:


I always turn these on and leave them on. 'Sub-pixel mapping' gives smoother results and 'Clamp output' stops any nasty over-bright bits.
(Yours may look different depending on your version of VRay)


System:


Last but in no way least, is this.

Frame stamp will place a bar at the bottom of your render showing the details choosen.

VRay log is handy if doing distributed rendering....otherwise it's just annoying....turn it off.

'Render region division' is the 'buckets' I was on about before, it's the squares you see when rendering.

These are linked to those two parameters in this way.....

If:
Bucket size=64
Min Value=0
Max Value=0

Then:
Irradiance resolution=64x64.....4096pixels/bucket.

But, if:
Bucket size=64
Min Value=-1
Max Value=-1

Then:
Irradiance resolution=32x32.....1024pixels/bucket.

The Image resolution is still the same but the amount of pixels used to calculate the irradiance map, (which is what makes your image look good), changes with those settings and the size of the buckets.(Render region)

If you have different Min/Max values then VRay will do two passes, one for the min value and if needed one for the max.

Don't worry about the maths here, it's just to show you how things are calculated and why changing a setting will alter the render.

So that's the render settings sorted, if you use these you won't go far wrong for a test render........but you need to also check your materials and lighting.

Vray will use standard materials and lighting without any problem, but light levels may need to be adjusted accordingly. One thing you can try first though, (before changing all your materials and lights), is to use a VRay camera rather than the standard camera, it gives you every option as if it were a real camera....apperature, film speed, exposure, focal length....etc. which means that if your scene turns out too bright you can just change the camera settings rather than your scene settings....very handy!

VRay cameras also give you the option to render DOF too.....bonus!


As you go through all the different parts of Max, you will notice lots of 'VRay' items popping up that were not there before, take the time out to explore them and look them up in the help files or on the net.....you'll soon see that VRay has lots to offer and is not difficult to use either.

So that's it really, a bit long sorry, but at least you have a starting point now. Another excellent place to start is.....

Aversis.be

....lots of good tutorials there specifically for VRay...(look under 'Aversis Extra' top right hand corner)

Hope that helps ya out for now, render that scene again and come back if you need anything.

Regards.