how to get a more realistic render using vray

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  09 September 2017
how to get a more realistic render using vray


Alslamu Alikum (Peace be upon you.. )

I was kindda wondering what do you think about this renderimages and whether if you could help me get better results for the render of
this scene.. actually i've hardly got to this result via adding displacement
map and HGlossiness to my materials which raised by result rendering time
enormously and literally made Max and the whole system freezes (it took cam_2
24min and 15sec to render a 800x600 pix preview).









the thing is that i actually saw tutorials about addingmaterials to a scene and it got better results with way less settings than i
had to this one so i think there must be something wrong with my scene that
needs someone else to critique.

Scene's archive on Google Drive

any thoughts would help.. appreciate it and thanks in advance
created with : 3ds Max 2016 - vray 3.2
PS: these are raw renders as it came from Max and were not retouched by any mains in Adobe Photoshop
 
  4 Weeks Ago
I actually think the image looks pretty good as it it. My main critique would be the wooden slats that you sit on. They have been modelled into the chair base itself, and usually they would be separate pieces nailed/glued together. This is making the box UV mapping look a little strange like it's veneer that has been glued over the sides.
Other than that, things look pretty good. Perhaps a little too many lights for a such simple scene.

1x VRay Sun
2x VRay lights
1x VRay dome light

A three point lighting setup would work just as well.

What system are you using? I opened your scene and set off a render of cam2 with all the settings you provided and the render finished at: 2m 52.9s. My system is first generation i7 so it's quite dated now.

Your VRay lights have their sample settings to 16 for each light. Due to the VRay sun there really isn't many shadow areas for area lights to generate noise, so you might get away with toning the samples down.

I also switched off the bump channel, as rendering with just the displacements gave exactly the same output as your image. Bump is not much in the way of calculations on a mesh like this, but it's certainly not needed.

Generally speaking I really think that it's realistic enough, apart from the specular. This chair is quite rough and I assume you have gone for the "varnished" look. You have pushed the reflective IOR to 8 to really push out the highlights. Wood is a soft material which blurs specular reflections. The highlights on your render to me would be a varnished surface but the displacements say different. Varnish generally has an IOR of 1.5 - 1.57. Sure your going to get much less reflections but you can work from there.

The 2 images are as follows. The first one is a straight render from your scene with no changes.
The second I have changed:
Material: The refection samples back to 8
VRay lights: All 3 back to 8 sampling

Material:
Reflection map removed from HGlossiness and placed in the RGlossiness channel.
Reflection swatch set to dark grey.
HGlossiness to 0.66
RGlossyness to 1.0
IOR to 1.5

The result is a lot less refective but looks more absorbent as I would imagine semi-rough wood to look.




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  4 Weeks Ago
Just to add. If you wanted a clear coat on this, that's quite easy to do. Ignore the funky reflections, the only thing this has to reflect is the 2 huge VRay lights from the front and left. You can see the displacements of the wood are still there but under a clear coat that is not displaced. The chair also keeps it's own specular as well. This could be done in a single shader but for ease of setting up I cloned the chair, added a push modifier of 0.001, and a shell modifier of 0.05mm.

Simple material setup.

Highly refractive material with a black diffuse as the main shader inside a VRay2sidedMaterial, with the transparency colour set close to black.

I can re-upload the scene file for this if you like.

Notice the rendertime has now doubled.


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  4 Weeks Ago
i can't thank you enough Glenn for your time and everything you've said and the tips for the 3rd render you kindly added..
you are right about how i wanted to get a varnished look for this material but i think i wasn't looking for the varnished look exactly rather than a deeper look makes me get to the point where i can't tell is it actually a rendered scene or a real photograph for this chair, this is why i went that far as for specular settings thinking that maybe this is the problem.

my system is :
- core I5
- ATI 1gb graphic card
- 8 gb ram
- win 8.1
- laptop "Dellnspiron n5010"

i really admire how u simply got to that very specular effect at the 3rd render but i think i would go for the effect in your 2nd render by the will of Allah..

i'll tweek these settings to the one's you've mentioned and hopefully render time is reduced as well as getting that beautiful look cuz if it didn't i'm not quite sure how will i get a higher resolution render if it takes 20mins for rendering a 640*480 pix.

sure i'd love to have a copy of your file if it wouldn't be to much trouble for you..

again i can't thank you enough for everything that you did to help me..
 
  4 Weeks Ago
No problem. Glad I was able to help.
Just remember that using lots of sampling for a ultra clean image is not always the way forward. It's a balance between noise and rendertimes. Get the noise to where you are happy and leave it. Otherwise you will be adding huge rendertimes for not much bonus for image quality. Remember that noise is almost unseeable in direct light, it's just the indirect light, shadows, reflections where the noise lingers.

Here is the file for you.

https://drive.google.com/file/d/0B0...iew?usp=sharing
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Last edited by ragupasta : 4 Weeks Ago at 01:40 PM.
 
  4 Weeks Ago
On a side note. Use render elements to troubleshoot possible areas. To to render elements and add the elements you wish to study. Do NOT enable them in the "Selected Element Parameters" as we want to study them in the VRay Frame Buffer (VFB). If you enable this, you need to set paths to write the images to disk.

Hit Render.

Then the top left of the VFB there is a drop down saying RGB Color. Change that to whatever you want to study. In this image I chose raw shadow. As you can see the white areas (ironically) are pretty noise free, apart from the very edges, but that is un-noticeable in the final render, so use these with caution. VRay will sometimes not fire samples into areas where is decides there is no need, so take into account that no all areas need samples.


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  4 Weeks Ago
Again i can't thank you enough Glenn..

I used the settings you recommended and rendering time literally decreed i to half (11mins), but onething i couldn't understand is what's the difference between bump and displacement map and when i should choose one over the other.. I mean i see that displacement map is giving the effect needed perfectly yet bump map added nothing. And also the same for Rglossiness and hglossiness as well.

I also made the same settings to nails material and decreased rendering time by 1min yet they still look strange specifically the ones of the back resting part of the chair..

the last thing i did was raising the displacement map from 3 to 5 and increased the reflection color a little bit (value 60), it's still a dark gray but maybe a little lighter sort of speak.
render took 14m 40s for 800*600 pix and here is the out come




i think eventually i'll have to retouch it in photoshop a little bit before posting it on behance, but i was wondering if there is a reason why the side of the chair is not showing any amount of bumpness in the texture as the front leg's front portion does and how much should the IOR for the nail become to make it look as natural as possible.

the last thing i wanted to ask about is that is their is a setting that enables me to save the render image with the render time from the VFB cuz i remebered it when i saw your render with the render time added in it that it can be generated automatically.. Thanks in advance
 
  4 Weeks Ago
Bump v's Displacements.

Basically a displacement shader will displace the actual geometry at rendertime (hence why the viewport does not update when enabled). Bump mapping works by displacing surface normals. In essence the actual surface is not deformed or displaced, just the shading normals of the geometry. You can see this by moving the camera to a glancing angle and render...the surface will be completely flat. Normal maps work in a "similar" fashion. For close up shots, displacements 100%. Distant shots, bump mapping will suffice.

As for the map that I put in the RGlossiness channel. The thinking behind this is, the highlight (for the clear coat shot) should be fairly smooth due to the multiple layers of clear coat and not really be affected by the chair geometry, that's why I removed the map from the HGlossiness channel. Reflections, I decided that the underlying geometry should affect the reflections, thats why I placed the map in the RGlossiness slot. Perhaps not 100% realistic but some degree of artistic-ness can sell a shot.

The nails basically want a dark grey colour, broad specular highlight, and a touch of relectivity. In your new shot, I think the specular on the nails on the side of the chair is too broad, looks kind of matte-plastic.

As for the displacements on the side of the chair, I wouldn't worry about that. Reason being is that: The side of the chair is quite literally a machined surface. It would be quite smooth, which play's true to the UV mapping you have on the sides.

IOR: This is an old post, but still exceptionally packed with IOR information. Please bookmark this, it's invaluable, (CTRL+F for the web browser search function really help, as this list is massive). http://forums.cgsociety.org/archive...p?t-513458.html

As for the timestamp on the render. That's easy!

At the bottom of the render there is a downfacing arrow called "Show Stamp Controls". Click this and it expands a lower area with a lot of confusing writing. This confusing writing basically tells you what will be shown on the bottom of the image. Each piece of information has a seperator "|". I just deleted all the un-relevant information for what I was trying to achieve. When that is done you "Apply Stamp".

See screen shot of said buttons.

Hope this helps.


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Last edited by ragupasta : 4 Weeks Ago at 08:04 PM.
 
  4 Weeks Ago
Also as a bit of fun, you can add whatever information you want to the stamp...


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  4 Weeks Ago
thank you Gleen for such detailed answer.. you can't imagine how much it was a great help for me..

BTW, i also took your advice on the 3 points lighting system for that chair "to be honest i didn't know about it tell you told me", i'm still sorting it out cause the seen looks darker and bluish cuz of the HDRI but i think it's giving more realistic look than using the dome and sun light "not sure why".. yet i don't know how this would end up looking like but i'll post the final render here in this topic after it's done by the will of Allah.. time render for cam 1 is almost 3-4min.

rendering the high reflective scene took 17mins

here is how far i've been to:



Last edited by Modather : 4 Weeks Ago at 12:48 PM.
 
  4 Weeks Ago
Glad to be of help. The lighting should be pretty straightforward, just a case of tweaking until you get the look you want. Only thing I'm noticing now on the distant shot, take a look at the chair legs. There is a repeating pattern of the texture map running down the length of the legs. You might need to tweak the UV mapping a little.
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  4 Weeks Ago
about the texture pattern, sadly the uvw map didn't give me a better options than this one or at least as far as i know how to use it.. maybe should retouch it as well in photoshop to fix it by the well of Allah
 
  3 Weeks Ago
Please post your final image when it is completed.
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  2 Weeks Ago
Alslamu Alikum (Peace be upon you Glenn.. ),

1st of All i really can't thank you enough on your help, i took your note about the tilling in leg's texture so i decided to unwrap the chair after trying to fix it unsuccessfully, which eventually led to remodeling the back seat and the setting bench as you'll notice, despite how frustrating it was, the results came unbelievably amazing and i finally achieved the look i was looking for, also after few tweaks "much if might say" managed to semi fix nail's material as well, one thing that i didn't manage to fix is how dark the scene is, it took 4 plane vray lights with multiper over 100 to light it up, yet as the colors felt little washed i replaced it with 3 spherical lights in a cone as a spot light which needed a multiplier over 500 for the key light and it still dark so i needed to fix it using photoshop while retouching them, shadows of chair legs on the floor plane don't seem right as you can also notice but i decided to end tweeking this project and publish it as it is already as i don't think it should take longer time than it has already..

here is a link to the final max file, please check it out and let me know where are my mistakes specially as for the light setup:
Wooden Chair

and here is a 2 previews for the raw render and retouched one's:









 
  2 Weeks Ago
i tried to keep retouch as simple as it could be so i used render elements (which i've to thank you for mentioning to in one of your replies here) and blending mood in photoshop, nothing fancy ..

one last thing, on behance as you may know i noticed a field in project's details to add a someone's contribution to the project details and i'd like to add your name if you don't mind, you've helped me a lot throw this project and i think it's the least thing i could do to you, so please let me know which name u'd like me to add by the will of Allah..

here is the project file on behance so you can see the rest of render views for this project if you'd like:
Project on behance

again, i can't thank you enough for your time and help
 
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