Please help me with my settings 101

[paulison]

Hi Everyone,

I just got my Vray demo last night and have till the end of the month to learn how to use Vray well (if possible). I have a few questions and notes on areas I am struggling with that

hopefully someone with experience can offer some help. Thank you guys in advance! Apologies for the large number of images - I have tried to keep them smallish.

1. What are some good glass settings balancing render speed and quality? my scene with no glass takes 2 hours, but with glass 48 hours. The glass looks very good but the rest of my scene sucks!

2. For materials, Should I use Vray Material for everything? At the moment most of my walls and ceilings are just standard viz4 material with an off-white diffuse colour. They look very flat but i'm unsure if this is my lighting or the material.

3. I have used a standard material combined with radiosity overide (following a viz4 tute) with self illumination for a recessed neon strip. This strip renders great at 320x240 with some nice glow, but at high resolutions it seems to be less bright. Is there a better way of doing this in Vray?

4. On a ceiling with a bulkhead I seem to get a light leak on the corner at the top of the bulkhead where it meets the ceiling. Im not sure if this is a modelling issue (modelled in ArchiCAD) or something that can be overcome with light settings.

5. My scene is lit entirely with photometric area downlights using some ies light settings from erco for the 'web'. I have a background environment map but no sun outside coming in. My scene looks dark, washed out and there is a lack of shadow difference on the ceiling and in recesses. I have been playing with the QMC system settings, Irradiance map for primary and global photon for secondary settings but I cant get it right . My guess on this is that my lights arnt emitting photon's (how do i do this?) making my global photonmapping settings irrelevant?

6. Having had many blotching problems in vray free I was told to fix this by removing all raytrace materials, but afterwards I was still getting blotching which is why I gave up and am trying the demo now. So far, using the demo and some settings found in a tute, I have no dark blotching, but there are still some artifacts in corners. Is this because I need more light in my scene?

Following these questions, I'll list out my settings which are mostly taken from a vray tutorial made by ozmosis where their simple interior scene renders very quickly but looks good (much better than my image looks!). I'll try and get screenies and the Image posted up soon which has been rendering for about 20 hours (1024x76 with really low settings. I am happy with this speed if the image looks good, but mine doesnt!. ..

Anyway here is some of my current presets and the scene im trying to render which I hope to improve on:




Vray Settings:






raytrace settings: - does this have any impact?



environmental settings:




Light settings: - photometric





Glass settings: - wow really bad eh




I've learnt more since beginning this render last night, but still need help on many of these areas just to help narrow down the key settings to adjust. As you can see, my image is very bad, but I think there is potential to make it good. Just some wise words to give some direction will help a lot!

Thanks again,

Paul



[/img]

[travistlo]

Right off the bat, I think the blur glossy in the glass material will increase your rendering, IES files are also slower. They look good, but slow.

[Psy]

Under global switches, turn off default lights. this will darken your image but will remove the weird default max light that shines from your camera in all scanline renders.

Under 'advanced irradiance map params', turn on 'check sample visibility' this should get rid of your light leaking from the bulkhead.

If the geometry is complex, in 'advanced irradiance map params' under 'interpolation type' use 'weighted average' instead of 'least squares fit'


That could help some with your render times and issues.

[travistlo]

1. What are some good glass settings balancing render speed and quality? my scene with no glass takes 2 hours, but with glass 48 hours. The glass looks very good but the rest of my scene sucks!

Im not sure if you want this or not, but make the glossy for your glass 1.0, the .97 is slowing it down

2. For materials, Should I use Vray Material for everything? At the moment most of my walls and ceilings are just standard viz4 material with an off-white diffuse colour. They look very flat but i'm unsure if this is my lighting or the material.

Vray Materials are faster, they can be a little but of a pain sometimes, but you can achive anything you need.

3. I have used a standard material combined with radiosity overide (following a viz4 tute) with self illumination for a recessed neon strip. This strip renders great at 320x240 with some nice glow, but at high resolutions it seems to be less bright. Is there a better way of doing this in Vray?

Use the standard material, but do not use radiosity override. Use the vral material wrapper, and increase the generate GI. Radiosity doesnt work with vray.

4. On a ceiling with a bulkhead I seem to get a light leak on the corner at the top of the bulkhead where it meets the ceiling. Im not sure if this is a modelling issue (modelled in ArchiCAD) or something that can be overcome with light settings.

psy had a suggestion

5. My scene is lit entirely with photometric area downlights using some ies light settings from erco for the 'web'. I have a background environment map but no sun outside coming in. My scene looks dark, washed out and there is a lack of shadow difference on the ceiling and in recesses. I have been playing with the QMC system settings, Irradiance map for primary and global photon for secondary settings but I cant get it right icon_sad.gif. My guess on this is that my lights arnt emitting photon's (how do i do this?) making my global photonmapping settings irrelevant?

Im not 100% sure of this, but i think someone will correct me, But I made a test scene to check. It doesnt look like the ies lights are producing photons. If this is true, use standard lights, they will produce the photons.

6. Having had many blotching problems in vray free I was told to fix this by removing all raytrace materials, but afterwards I was still getting blotching which is why I gave up and am trying the demo now. So far, using the demo and some settings found in a tute, I have no dark blotching, but there are still some artifacts in corners. Is this because I need more light in my scene?

You will have to render with higher settings, search around the fourm there are a lot of topics about that. Most of the time, its just the hsph subdivs are too low.


Change your glass, and If you can your lights, make sure you remove the radiosity overides, your render times should get a lot better.[/quote]

[paulison]

Thanks for the great help so far guys.

I'll try all of these things out and post a new image and render time once i'm a bit happier with it. I think part of my problem is the modelling...lot of polygons in this scene that dont really need to be there due to it being done using ArchiCAD.

[paulison]

Im trying to figure out what the 'blur glossy' setting is for glass.

should i change the subdivisions from 50 down to say 5?

with reflection interpolation should i reduce the samples from 20 to say 10?

These are a couple of other ideas I have but will they make a speed difference?

[percydaman]

when using interpolation, use high numbers 50 and above. when NOT using interpolation use low numbers, say from 8 to as high as 16.

[paulison]

Thanks Percydaman. I have seen similar comments in other threads but wasnt sure untill now exactly how that worked.

would the speediest solution be to render without using interpolation with a setting of 8?...

or using a high setting with interpolation?

I'd guess a high setting with interpolation gives the best looking results?

I cant do speed tests till tomorrow night to find out for myself because this IR map is rendering and my computers are already maxxed out in terms of resources.