First test on OSX

[raiusora]

Hi Guys,

I've made a little test to compare the pros and the cons of VRay on Modo, and here are my thoughts:

I'm working on Modo since the 501 version on OSX (yeah they like Apple where I work...), and this is my first "in depth" test with VRay. I'll use raw renders of course.

But the first point that I'd like to know is why the result on the VFB and the saved image is different?





So for the comparison I'll use the VFB image.

Here are the the 2 raw renders:





I first had to make some tweaks with VRay materials because the Modo's settings don't work so well with VRay


Cons:

_I find the result to be quite saturated, the wood turns too red and I could'nt get the brown aspect of Modo without desaturate the image map.

_The refraction on the glass doesn't have any absorbtion

_The render took about 25 minutes on VRay with the GI default settings and took only 15 minutes with a 16 samples antialiasing 128 indirect rays and 6 bounces. Well it may be partly that as I don't know VRay well, I didn't know how to tweak it correctly.


Pros:

_The color bleeding is better on VRay, it gives a sentiment of "more finished"

_The "reflection glossiness" works better than the Modo's "blurry reflection", I didn't get the reflection bug on the left side of the stairs.

_The different shadows blend better on VRay and are less noisy.


And here are some problems with the workflow that I found:

_The camera offset doesn't work (but I've read it' was about to be correct)

_When you use VRay materials, it turns to be juste white in the OpenGL, it's quite annoying when you can't even see the transparency on the glass

_There is no Preview, when you are used to work with the Modo preview, this is a great loss.


That's all for the moment, hope this is gonna help someone in any way.

[vladimir.nedev]

Hi,

Can you tell me what color corrections you used in the VFB when the saved image and the VFB image were different ?

The difference in the wood texture might be because we ignore the new "colorspace" feature in MODO 801. I will try to fix this for the next build.

The absorption equivalent in the V-Ray material is the "Fog color" and related properties. You can read more about it in the V-Ray for 3ds Max help here :
http://docs.chaosgroup.com/display/V...ColorParameter

The V-Ray materials not working correctly in the OpenGL view-port is a MODO API limitation present on all "custom materials"
(i.e. everything that is not MODO's main material). You can file a request to the Foundry. I've already mentioned it, but users
complaining might make it more urgent for them.

V-Ray's preview is the RT CPU renderer. Admittedly, not all changes to the MODO scene are updated automatically right now.
But you can still do a lot of tweaking - modify material properties, light properties, add/delete/move lights and meshes, change the
environment, change the current frame, add/delete textures in the shader tree.

Greetings,
Vladimir Nedev

[raiusora]

Hello,

First thank you for your answers Vladimir,

Concerning the color corrections in the VFB, well I didn't make any, I've just hit the save button right after the end of the computing.

Indeed I didn't thought about the RT render, I'll try it today.

And I'll post a request about the OpenGL viewport to the Foundry.

I'll tell you if I have other remarks.

Thanks again.

[raiusora]

Hello again,

First I completely forgot to tell you that I actually work on the 701 version of Modo, maybe this will explains some problems...

I've run a new test and there's a point with n-gones.

here are the pictures:











Yeah the model is a complete crap, for a reason of time I had to export the sketchup model and use it as it was. And there is still a difference between the VFB and the saved image.

I tried to replace the modo materials with the vray one but there was no change (knowing that the same model rendered with Vray for Sketchup doesn't have this problem either). So what can I do to avoid this problem? Of course I could remake the model with a proper polygon flow, but I don't always have the time to do this. If there's any other solution, it would be great.

Thank you.

[vladimir.nedev]

The n-gons problem is specific to V-Ray for MODO 701. It is fixed in V-Ray for MODO 801. The MODO 801 API has functions for triangulating such
polygons properly, whereas V-Ray for MODO 701 uses a simple algorithm, which breaks for concave polygons. Writing a better one which
works in all the edge cases will be a significant task, so we won't do it for now.

What you can do is :
1. Select all concave polygons of your mesh ( you can easily do this by going to the Info & Statistics viewport and then Polygons -> By Type -> Concave )
2. Execute MODO's triangulate command ( Main menu -> Geometry -> Polygon -> Triple).
This should fix it.

Can you tell me what format you are using to save the images from the VFB ? And also what image viewer you are using to view them afterwards.

Greetings,
Vladimir Nedev

[raiusora]

Ok I think it is time to switch to the 801 version

I save the images in PNG format and I use the default image viewer of MacOS to view them.

There's also another point I've just found concerning the render(s) output(s), everything at the top of the shader tree is rendered in the VFB:



But the render output specific to a material seems to be ignored:



Is it also a 701 specificity?

Thanks.

[vladimir.nedev]

Masking the render elements is not working in V-Ray for MODO currently (doesn't matter whether it is MODO 701 or MODO 801).
We are hoping to make it work at least for the "Alpha" render output in one of the next beta versions, but this is not implemented
in the V-Ray core yet, so it will be a bit harder than some other stuff.

Greetings,
Vladimir Nedev

[raiusora]

Ok thank you for all the informations so far

Greetings.

[vladimir.nedev]

So I've investigated the issue of the VFB window and the saved image not being the same.
It seems we are not correctly "tagging" the pixels in the VFB as being in sRGB color space, so the correct result is the saved image.

Greetings,
Vladimir Nedev