Author Topic: Vray user (almost Ex) , first impressions, troubles and suggestions  (Read 9545 times)

2014-01-18, 00:08:10

benjamincillo

  • Active Users
  • **
  • Posts: 31
    • View Profile
Hi guys

First of all, I want to thank the corona developers for such impressive rendering engine, really nice results in a few clicks!

I'm an intermediate Vray user, but in this two days I gave myself the opportunity to try Corona, and get easily involved, after looking the galleries with user's works, I guess it's time to move on...

I share with you my first test image for a WIP scene, very basic, but I would like to improve with your opinion ans suggestions, as well to ask some questions:

Corona was set to default values, except for

-LUT Gamma, enabled to 2.2
-Exposure: 9
-Highlight compression:30
-PT samples: 1024 (I read somewhere it can improve image quality)

MATERIALS

1. I just import some vray objects and convert materials with DeadClown's Advanced Corona Material Converter (http://forum.corona-renderer.com/index.php/topic,126.0.html) but I noticed items must be un-grouped previous to convert them, is a bug?
once converted materials lost specular levels or difusse maps are not correctly shown. please look at the plants

LIGHTS

2. Is there a way to hide the "solid volume" from corona lights? I mean, is kinda annoying to add some lights on windows and then get a solid volume which doesnt allow me to see thru the scene. Something like "wired" or non-solid light?

3. It makes me wonder: Is it really needd to add some lights on windows or spherical lights for interior scenes? at the end I just used a HDRI map as only light source.

CAMERAS

4. I love the option for correcting white colors with color maping post process in real time, but some times, depending on lights sources I have to change those values each time I need to get a new image, also, by doing this way, I will not remember the settings for each camera :(.

Plase add something like vrayphysical camera, in order to control DOF, Exposure, Highlights, contrast WB and so on. Please add the option for controlling those values on camera while rendering too, its a cool option!

OTHER

5. I set the same rendering time from my vray scene in order to compare image quality. As you can notice, Corona image seems to be more "blurred" at background.
There is away to improve or change Antialiasing? how can I clear noise?

6. I use the VFB + plugin (http://www.scriptspot.com/3ds-max/scripts/vfb-a-feature-rich-extension-to-the-3dsmax-frame-buffer), wich adds the option to load image files to compare with a slider , and also a filmstrip where you can see and "rescue" a previous rendered image. I similar option for Corona will be really nice.

Thanks!

 
« Last Edit: 2014-01-18, 22:07:53 by benjamincillo »

2014-01-18, 08:46:20
Reply #1

Stanislav_But

  • Active Users
  • **
  • Posts: 525
    • View Profile
    • https://www.behance.net/archdizs
Hi, man!
U used alpha of half-year old. Will be new alpha with more new cookies soon. We belive))

All corona's maps doing good in alpha 5 - try to check your settings. To decrease "to much noise" try to set low multyplayer of bump

2014-01-18, 11:34:52
Reply #2

Ludvik Koutny

  • VIP
  • Active Users
  • ***
  • Posts: 2560
  • Just another user
    • View Profile
    • My Portfolio
1, Do not write thread titles with all capital letters - it makes you look like a douchebag and possibly decrease amount of people who will visit your thread to give you an advice. ;)

2, Setting PT samples to 1024 is a nonsense, as you will get almost no antialiasing. What you have read is probably to set PT samples in !HDcache! to 1024. It was a big mistake that two settings were named the same, and it will fixed in next version. :)

3, Your materials look crappy because you used converter, instead of redoing them from scratch and learning how CoronaMTL works. Converter is just an aid tool for people who know what they are doing and need to convert some scenes. But it never works 100% without manual clean up. So if you are new to Corona, then avoid converter and do materials from scratch.

4, Why do you put lights in windows? Corona environment lighting is nearly as fast and accurate, Just put your environment map into environment slot. Just put your HDRI into environment slot, that is absolutely all.

5, Physical camera is already added and will be available with next public alpha. It will not be adjustable during rendering though.

6, Your scene is slow because you do not know what you are doing. If you were new to Vray, you would end up the same.

Most common mistake is glass with refraction set to solid mode. You have to use hybrid glass. Solid means everything behind glass surface is computed as caustics, so if you put solid glass in window, you will seriously slow down your scene. We admit that refraction modes are really badly named and create a LOT of confusion, so we already fixed it for next public alpha version.

Another very common mistake is too high albedo. Fresh mountain snow is about RGB 230 white... arch of white paper is 220, and white walls are usually around 200-210. People often have 250 or even 255 white on their walls and wonder why their scene converges so slowly.

Next common mistake is changing max. sample intensity from it's default value. It will give you some additional accuracy, but may radically slow down your render.

7, VFB+ is really great, so if you have bought it, then stick with it ;) There is only one developer of Corona, Ondra, and while he can do some VFB improvements, he will never be able to do as perfect framebuffer as a person, who can spend all of the time programming just VFB.


Here is a simple guide which if you follow, you will almost always get a fast and clean result:

1, Make a new empty scene, switch renderer to Corona, and keep everything at default except setting secondary GI to HDcache

2, Merge contents of your scene into this new scene, but do not merge lights, merge everything except lights. Daylight system is a group, so if you have that, and merge it with other stuff, just make sure to delete it.

3, Create new CoronaMTL with default settings, and assign it to ALL objects in the scene.

4, Select all object, open object properties, and make sure there are no fakes enabled, such as disabled camera visibility, or disabled shadows. Fakes in Corona, if used unwisely, may actually lower performance.

5, Go through the scene, and hide large glass objects, that would occlude a lot of scene surface from lights. That means glass planes in windows and glass walls or glass railing sections. You do not need to hide small stuff, like glasses on the table, chandeliers, or small glass statues.

6, Open your environment dialog, click the map slot, add bitmap, and load your HDRI or even low dynamic range environment map.

7, Do a test render, you should have nicely lit render with gray material. Now it is time to adjust exposure settings, and possibly rotate your environment map to get the lighting you want.

8, Add artificial lights, like cove lights or light bulbs in your scene. Add them one by one, and observe if any of them creates noise that is going away a lot slower than other lights. If that is the case, then go take a look what is wrong with the light. It may be intersecting something, be oriented in wrong direction, or something like that. Try to not use directionality feature as it is not very optimized at the moment. IES are also a bit slower than regular lights, so use them only when you really need them.

9, Once you have all the lights added, and tweaked to your lighting, start to add materials one by one. Start with a white wall for example, and make sure you do not create superbright materials as i mentioned above. I usually do not go over RGB 210. If i have a texture that contains pure white color, i just change output value in bitmap to something like 0.8-0.9.

10, Now that you have all your materials and lights done. Create a new material, make it a glass (reflection and refraction IOR at 1.52 and reflection and refraction level at 1), and set refraction mode to hybrid. Now unhide all those large glass objects you have hidden previously, and apply this material to them.

11, Tadaaaa, you should have fast and optimized scene! :)

Seriously, if you follow this guide, there is a very few things that could go wrong.
« Last Edit: 2014-01-18, 11:51:30 by Rawalanche »

2014-01-18, 11:59:08
Reply #3

LKEdesign

  • Active Users
  • **
  • Posts: 83
  • I'm addicted to Corona Render and I need NO cure.
    • View Profile
    • LKE Design Web-site
This guide above should be cut out, saved as a PDF and shipped with all future alpha's - and maybe better be shown as a text box once you change render to Corona (with the option of hiding it once and forever, once you've got the general idea)!

Good work, Rawalanche - I look forward to the Corona beta'a, where I understand that you will be the author of the documentation.

All the best,
LKE Design
See my work at: http://www.lkedesign.dk/en/portfolio_en.html

2014-01-18, 12:10:15
Reply #4

Ludvik Koutny

  • VIP
  • Active Users
  • ***
  • Posts: 2560
  • Just another user
    • View Profile
    • My Portfolio
Good work, Rawalanche - I look forward to the Corona beta'a, where I understand that you will be the author of the documentation.

There should be already some for Alpha V6. And if everything goes right, it should be embedded right in 3ds Max UI in form of tooltips when you hover over spinners and buttons.

2014-01-18, 14:43:12
Reply #5

LKEdesign

  • Active Users
  • **
  • Posts: 83
  • I'm addicted to Corona Render and I need NO cure.
    • View Profile
    • LKE Design Web-site
Fine fine, but the 10 commandments to success in Corona shouldn't be hidden in some tooltip, I think. :-)
All the best,
LKE Design
See my work at: http://www.lkedesign.dk/en/portfolio_en.html

2014-01-18, 14:59:07
Reply #6

Alexp

  • Active Users
  • **
  • Posts: 153
    • View Profile
I think this is good idea. If anyone look at the graphic bar in this thread (http://forum.corona-renderer.com/index.php/topic,88.0.html) can realize that the vast majority is coming from vray.

I think a PDF or a organized document for the conversion is needed.

Thanks for the the initiative.

2014-01-18, 17:40:56
Reply #7

Ludvik Koutny

  • VIP
  • Active Users
  • ***
  • Posts: 2560
  • Just another user
    • View Profile
    • My Portfolio
I hope that benjamincillo will return to post the result, because i am curious if the guide was actually helpful. It's not hard to write it down... but if it works, that is a lot different story. ;)

2014-01-18, 22:27:45
Reply #8

benjamincillo

  • Active Users
  • **
  • Posts: 31
    • View Profile
Hello guys

First, I want to thank Rawalanche for those value tips, not only for me, but also the whole community
I will try your sugestions and post results nex week

Sorry for writing in capital letters, didnt want to be rude.

Just two more questions:

-concerning about albedo value, what do I have to change? difusse or reflection level?
-concerning about mergin objects to scene: do you suggest to re-make all materials, one by one... :S ?

ps. I start the scene from scratch, I just convert the plants and the vase. but this concrete wall is getting me crazy!, as well the strange behavior on those converted materials.

2014-01-18, 22:31:50
Reply #9

LKEdesign

  • Active Users
  • **
  • Posts: 83
  • I'm addicted to Corona Render and I need NO cure.
    • View Profile
    • LKE Design Web-site
Now we all are gathered :-)  .....
About lighting. Is there anyone that can tell what kind of unit or measure that is being used for the emission, - and even better could anyone give me some equivalent value(s) to the real world.
As I understand the value is area based - in other words, it doesn't matter wether it is placed on an 1x 1 cm object or or an 1 x 1 m object, the light has the same strength, right?

And as I understand it shouldn't matter wether I'm using a corona light set to a rectangle of 1x1 m or if I make a material with emission set to the same value and put it on a plane in same size, right?

The tricky thing is, - again, as I understand- , if you use a corona light with an IES profile - and you then want to make a mesh of fx. a lightbulb to look glowing, as IES lights are measured outside of a given fixture, giving the total light distribution.
If you chose to let the IES light light the fixtures mesh, it would be wrong, as it would fx. light the shades inside with the light distribution from the total fixture. AND if you use a material to make the lit components glow, then it would not be right to, because this would distribute both the light from the IES light together with the emitting material - as I don't see any setting for not letting the material emit light - just look like it does.  Correct me if I'm wrong.

It's for sure easier to put in a Corona light or material and let it mimic the fixtures light source (the bulb) and then let it distribute light inside and outside the fixture. It wouldn't however  "hold in court"  in the documentation for a light distribution as you can't be sure the various components in the fixture are modeled right, if they all are there and have the right material ect ect. That unfortunately is certified to be right in IES profiles.

You might say, - hey, we are only doing visualizations - yes, but it's always good to know if we are doing all physically correct or not - especially if we are going to deal with things likephysical cameras ect. and am wondering why things are not looking like on photos anyway.

Still, I may stand corrected - and please do if I'm wrong.



« Last Edit: 2014-01-19, 00:19:25 by LKEdesign »
All the best,
LKE Design
See my work at: http://www.lkedesign.dk/en/portfolio_en.html

2014-01-18, 23:47:11
Reply #10

Ludvik Koutny

  • VIP
  • Active Users
  • ***
  • Posts: 2560
  • Just another user
    • View Profile
    • My Portfolio
Hello guys

First, I want to thank Rawalanche for those value tips, not only for me, but also the whole community
I will try your sugestions and post results nex week

Sorry for writing in capital letters, didnt want to be rude.

Just two more questions:

-concerning about albedo value, what do I have to change? difusse or reflection level?
-concerning about mergin objects to scene: do you suggest to re-make all materials, one by one... :S ?

ps. I start the scene from scratch, I just convert the plants and the vase. but this concrete wall is getting me crazy!, as well the strange behavior on those converted materials.

Albedo: Diffuse. Reflection should be energy conservant, so you should be fine. That being said, i rarely use reflection over 0.9. I never use 1, and i use 0.9 only for things like chrome or fine polished steel ;)

Merging object: Yeah, remake all one by one. It should not be that hard. There is around 10 materials in the scene ;) I think it would take me personally about 15 minutes ;)

Just try to follow the steps in guide exactly, and if you get stuck at some point, then post a picture with problem description. I will try to help ;)

2014-01-28, 13:13:29
Reply #11

Utroll

  • Active Users
  • **
  • Posts: 164
    • View Profile
6. I use the VFB + plugin (http://www.scriptspot.com/3ds-max/scripts/vfb-a-feature-rich-extension-to-the-3dsmax-frame-buffer), wich adds the option to load image files to compare with a slider , and also a filmstrip where you can see and "rescue" a previous rendered image. I similar option for Corona will be really nice.

Thanks!

What Rawalanche means by "stick to it" is that VFB+ works flawlessly with corona too,
just switch vfb type to default instead of corona's built in 'customWxWidgets' and if you have vfb+ overriding the default max you're back to your uses.
Everything work, render pass switch, even stamping whatever render's parameters from Corona's core.


!!! The only thing I could see improved is the corona's settings 'post production' are not reflected when render is stopped : at render time changing the highlight compression would reflect in render view (Wx or VFB+), after pushing stop it's not working anymore in VFB+ while it stills alter the image in the WxWidget. That is probably not much informations to exchange between Corona's dev and VBF+ dev to make it fully integrated.
« Last Edit: 2014-01-28, 13:19:02 by Utroll »