Capturing very detailed normal maps using Photometric Stereo (R&D)

By | Dabarti | One Comment

Photometric stereo.

A while ago I did small research project with the aim of developing best way to acquire accurate normal bump maps from photos. In this post I’m going to describe how I did it.

Initial idea was to use Agisoft and photogrammetry, this seemed as the most straight forward approach, but while it produced some promising results I found that detail of the textures was not nearly good enough. After going though some papers on that subject I struck gold by stumbling upon technique called Photometric Stereo.

Great explanation of what it is and how it works is found on Wikipedia.  What I love about this idea the most is that I could potentially take photos from single point of view and generate normal map with the quality limited only by the lens and camera sensor. Think about this like “reverse rendering”. If you know the color of the given part of the object and direction of the light, you can basically find out the surface normal.

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Interior rendering with V-Ray RT GPU 3.5 based on Evermotion scene.

By | Blog, Dabarti | 6 Comments

Today after quick chat with Michał Franczak from Evermotion I’ve decided to test how hard it would be to render one of their scenes on GPU. They have kindly provided Archinteriors vol. 42 for testing and it gave birth to this quick test.

It did turned out easier than I expected. Here is video I’ve recorded of the process:

At first I tested how the settings from older V-Ray are holding up. Than I did 1 min test render with Adv CPU for reference.

Converting to V-Ray RT GPU 3.5 was as easy as switching rendering engine and using CUDA instead of CPU.

Here are rendering results ( I raised LC samples back to 1000 after recording the video for the finals rendering ):
RT GPU render with threshold 0.01, no denoiser. (28 min 52 sec)
RT GPU render with threshold 0.05, with denoiser (7min 57 sec)
Adv CPU render with threshold 0.01, no denoiser. (1h 48min 53s, lighting difference caused by skylight portals)
Rendered on 400USD GPU – GTX 1070 8GB.
For CPU I used 4770K overclocked to 4.2Ghz.

It took only around 3GB of GPU memory for the scene. I was also able to drop it down to 2GB with on demand textures switched on.

Original CPU renders and scenes are available on Evermotion website.


Review of V-Ray RT GPU 3.5 (Based on Beta 2)

By | Blog, Dabarti, Our creations, Software, Tutorials, Updates | 2 Comments


It has been over 7 months since the release of earlier Service Pack and we will be getting another free upgrade in Q1 of 2017. It’s now in public Beta stage. In this post I point out and review newest features and improvements of upcoming V-Ray RT GPU 3.5. I will focus only on GPU side of the engine as I think it deserves way more exposure than it gets. While it may seem like a small addition to V-Ray CPU (Adv) it’s in fact full-blown production rendering engine that paves the way for better and faster rendering workflow.

Over the course of last months I’ve been crazy enough to keep installing latest Nightly builds of V-Ray RT GPU on regular basis and abusing the hell out of it. As I’m sharing all the my testing data, bug reports and improvements ideas with Chaos Group team I also feel partly responsible for its current shape.

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Procedural bump in V-Ray GPU (RT) 3.5

By | Dabarti | No Comments

Good news. Procedural bump is coming to V-Ray RT GPU with next service pack and it’s looking great.

For now only “Noise map” is available from procedural XYZ noises, but combined with mapped gradient ramp, output map, mix and composite I was able to get broad range interesting shaders. Hopefully more types of noises will be added soon.

From technical stand point they seem to be sampled very well. I was worried that it may slow down rendering, but that wasn’t an issue. Also it’s important to use VRayColor2Bump, otherwise things won’t work correctly.

I’ve recored how I did setup all of above shaders.

Check it out here or on our Youtube channel.

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Testing Adaptive Lights in V-Ray 3.5 Adv (SP5 under development).

By | Dabarti | 6 Comments

Something very good is about to be added to V-Ray. It’s called Adaptive Lights and it speeds up rendering huge amounts of lights. Still under R&D but it’s already very impressive. And It makes me very happy as for quite some time I’ve been unimpressed by the speed of rendering lots of V-Ray Lights. As usual Chaos Group team listened and created something simply amazing.

I’m excited. Check out why:

For this image render times went down from 43:37 to 10:29 :

For this one render times went down from: 53:59 to 7:31

I trust numbers and like to test a lot on variation of scenes. So I took shots we did in the past and calculated how much faster it would be on average compared to Probabilistic Lights or Full approach:

My personal thoughts based on those tests:

  1. Probabilistic lights are not universal solution for scenes containing huge amounts of lights.
  2. It’s smart, it adapts to the conditions of scenes and users don’t have to worry about playing with settings as much as they had with Probabilistic lights.
  3. New approach is more universal and compared to Probabilistic Lights it will be a lot faster.
  4. More lights = bigger the difference. It will render very fast regardless of number of lights.
  5. It’s good to complain that something is slow ;)…

If you have access to nightly builds, you can test it out already (use maxscript code for that “renderers.current.options_probabilisticLights=2” ). This is still under research and development but it’s supposed to be included in next service pack.

If you would like to learn more about adaptive lights I recommend you to visit this ChaosGroup Lab blog post .


Short guide to GPU rendering with V-Ray RT.

By | Blog, Dabarti, Tutorials | 16 Comments

The aim of this guide is to help with switching to rendering on GPU with V-Ray and has all the basic information needed to better understand advantages and limitations of this approach. Everything below this point is based on our experience with using V-Ray GPU (RT) as our main production renderer.

1. Why GPU for rendering?

It all started around 18 months ago when we decided to do a hardware upgrade to get better 3ds Max viewport performance. So we installed new GPUs (it was GTX970 4GB) and decided to see how things improved with rendering on GPU with V-Ray RT. We loved it!… Well, to be honest not straight away. It took time to change the mindset, but the speed boost and interactivity were there to help and sooth any pain caused by some V-Ray Adv features missing.

It wasn’t the first time I tried rendering on graphic cards. But back when GPUs had 512-1024 MB of memory it wasn’t really a production ready solution (at least for us). It changed with launch of Nvidia’s maxwell cards that came with 4GB on board, did cost fraction of their Quadro brothers and were much faster and more energy-efficient than earlier generation. This alone made it possible to render 70-80% of our scenes.

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Dabarti Light Assistant

By | Blog, Dabarti, Free Stuff, Tools | 6 Comments

Light Assistant helps with aligning reflections and adjusting the parameters of V-Ray lights.

Main features:

  • Interactively ALIGN lights reflection directly on the geometry. Hold shift for “Rim Light Mode”.
  • Interactively change light distance, size and rotation in ADJUST mode..
  • Quickly control V-Ray Light properties with “Light Lister” like interface.
  • Adjust light intensity using Exposure Value (EV).
  • Align and Adjust modes work well with some non V-Ray lights.
  • 10 Softbox presets in material library included.
  • Designed to work perfectly with V-Ray GPU (RT)


Download : Dabarti_Light_Assistant_v0.802 (2nd October 2016)

(Please link directly to this page as the tool gets constant updates this version will be outdated in near future.)

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Using V-Ray denoiser tool (vdenoise.exe) with send to scripts + Backburner submission.

By | Dabarti, Tutorials | 7 Comments

General Idea.

This is going to be quick tip for anyone who would love to easily denoise sequence of exr files with vdenoise.exe without typing in commands manually. This workflow could also be used for number of different tools or scripts like encoding video with ffmpeg or converting exr sequence to mov using DJV.

The trick is to use windows send to scripts. If you don’t know it yet, in Windows you can create custom .bat files that will run commands from under right mouse button’s send to menu. This is very helpful if you want to automate some file processing tasks and save a lot of time in the process.

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Building 4xGPU rack-mount rendering node

By | Dabarti, Tutorials | 33 Comments

Few months ago we build 2 custom GPU rendering nodes. I’ve decided to share all the specs of what we ended up buying to make it easier to anyone who wants get something similar.  

List of components:

  1. Rack mount case – Chenbro RM413 4U + 8 PCI rear back window (55H103413B007 + 55H173413B001) – 142 Eur + 15 Eur  = 157 Eur . You have to unscrew the rear window that comes with the case and replace it with extended one or instead look for Chenbro RM41300-FS81 which already has 8 slots. I wasn’t able to buy this one but it’s out there.
  2. Motherboard – MSI X99A XPOWER 390 Eur . This one is relatively cheap and has 2 x 1Gbit Ethernet connection.
  3. PSU – Enermax Platimax 1500W modular with 90-95% efficiency 290 Eur, enough to supply power for all GPUs,
  4. Memory – Crucial Ballistix Sport 8GB DDR4 x 4 = 211 Eur.
  5. CPU –  Intel i7-5930K 3.50GHz 15MB BOX = 560 Eur
  6. SSD –  Samsung 250GB 850 EVO = 85 Eur.
  7. OS – Windows 7 PRO = 90 Eur

Total without GPUs = 1783 Eur

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360 Stereo VR renders.

By | Dabarti | No Comments

Best way to view those renders is currently implemented into Virtual Desktop – Cube 360 Stereo renders are recommended, but I’ve included Spherical projection as well. Resolution is a bit higher than needed for Oculus DK2 and it’s 24 000 px x 2000 px for Cube mapped renders and 8 000 px x 8 000 px for Spherical.

Radiostation. Download for VR: Cube 360 or Spherical 360.

Subway. Download for VR: Cube 360 or Spherical 360.

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