Some beginner questions, texturemapping, GI modes etc...

[pwrdesign]

Hi All!

 

I'm totally new to Vray, just opened it...

Been working with maxwell for about 5 years though so I'm pretty experienced with rendering in other softwares.

 

We are looking at Vray as a complement to Maxwell, especially for animations, and I've started to do some tests.

 

Got some pretty major problems though.

The model is modeled in Rhino, exported to DWG and (not my stuff) and I've linked it into 3dsmax.

 

1. I'm trying to create some simple panels for the facade...

This is the diffuse map I'm using:

 

http://img198.imageshack.us/my.php?image=standingboards30x30diff.jpg

 

and this is the bump map:

 

http://img196.imageshack.us/my.php?image=standingboards30x30.jpg

 

The scale for those I've set to 30cmx30cm, using real world units.

 

I can't get the texturing to work though, could this have anything to do with the 3D objects I have to map?

 

http://img191.imageshack.us/my.php?image=testrender.jpg

 

Settings for the diffuse map:

 

http://img44.imageshack.us/my.php?image=boardsmaterial.jpg

 

2. I'm trying to create a good grass texture, and I've done about 4 different tutorial, but I think that the render time takes too long..

The Fur-way of doing it is way to time consuming when rendering, and I cant get a nice result with Vraydisplacementmod I have tried all kinds of settings...

 

3. For the light I'm suing a HDR as reflection map and a VraySun as Sunlight.

I've turned GI on, using Irradiance Map and Light cache... Low settings for Irradiance map and about 500 subdivs for the light cache, the rest as default. Does that makes sense?

 

4. I've tryed to xref some max-files of Xfrog trees and Onyx Trees, but it directly turns my rendertimes to hours instead of minutes

 

5. At the moment I'm using the demo version of Vray, (our licenses should arrive tomorrow) can I get it verified that the settings I make in the render setup resets every 5-10 minutes due to the demo version? Also, I cant use the distributed rendering with demo-licenses?

 

My workstation is an i7core extreme with 12Gb ram.

 

Any help would be appreciated.

 

best Regards Patrik

[pwrdesign]

Never mind about number 1, looks like it had to do with the DWG file..

We imported it as a FBX file instead, and I finally see my texture when I render.

[pwrdesign]

Noone?

[Thablanch]

2 - Grass is a gice and take.. you can get away with texture or a photoshop photomatch in post prod. ( some mix-maps can produce nice results as well) But yes, it is time expensive.. should not be hours with the machine you have, but for sure a couple minutes more. If you are using displacement, make sure to use the 2d displacement.

 

3 - makes sense.. HDR wil bring you reflections, it is a good way to work.

 

4 - same here as grass.. a single tree is probably more geometry than your building itself, plus the renderer has to deal with opacity maps..

Again, with your machine, should not be hours, but if you are concerned about render time, look at what you can include in post prod.. does the trees miles away behind your building really need to be 3d.

 

5 - Can not really tell about the demo limitations.. but once you will have your license, you will see that Distributed rendering is soooo great....

[bragibjornson]

Some quick thoughts:

 

Got some pretty major problems though.

The model is modeled in Rhino, exported to DWG and (not my stuff) and I've linked it into 3dsmax.

 

-All i can say is the more complicated (more steps/programs) in your workflow - the more likely your going to run into problems. The more you do in your final program (3dsmax?) the more consistent results that you'll see - although it seems like you're already tweaking your workflow to remedy this.

 

Render Times:

 

Im seeing this comment alot in your post - the hard thing to determine is what's ALOT? My typical rendering is 12 megapixels (4kx3k) If i have a full size final render that takes more than 2 hrs on my machine (NO DR - which is probably

 

2. I'm trying to create a good grass texture, and I've done about 4 different tutorial, but I think that the render time takes too long..

The Fur-way of doing it is way to time consuming when rendering, and I cant get a nice result with Vraydisplacementmod I have tried all kinds of settings.

 

Some Options here are:

 

A. Paint the grass in a compositing program using photo source

 

-find or paint yourself a sizeable texture using source thats close to the specific camera angle your at. If you comfortable with composting (photoshop) its a quick exercise. Good method for one still, if doing multiple, Id suggest expoloring something in 3d.

 

B. Use combination of mix diffuse maps (to prevent tiling) and use different map channels (so you could add effects atop the diffuse map in the shader)

 

-there is no one texture that will give you a good grass texture without repeating. use the mix maps make the grass tile less, and you can add details (patterns, etc.) by mapping "effects" on different channels.

 

C. Vray Grass:

 

-this is what i use. Render as a pass and comp into scene with a matte. I wouldn't render in scene - its unecessary and will only take longer.

 

D. Vray Displacement:

 

-could be possible. If vray - make sure you use the VRayDisplacmentMod, NOT the displacement modifier in the material. VRDM is MUCH faster. Follow Thablanch's recommendations - use 2d disp, not 3d.

 

Use all above in combination. Maybe you only need the VrayGrass or Displace Grass close to the camera - and far away it can be a map...

 

3. For the light I'm suing a HDR as reflection map and a VraySun as Sunlight. I've turned GI on, using Irradiance Map and Light cache... Low settings for Irradiance map and about 500 subdivs for the light cache, the rest as default. Does that makes sense?

 

Yes.

 

You might consider using exposed Vray Camera set to the sunny 16 rule, and just a Vray Sun and Sky. This renders well, consistently and quick, and its all native to VRay. The only thing is you lose some of the lighting details you get when using HDRIs.

 

4. I've tryed to xref some max-files of Xfrog trees and Onyx Trees, but it directly turns my rendertimes to hours instead of minutes.

 

Did you put the onyx trees directly into your scene (rather than xref) this should test whether your slowdown is related to the mesh or to some sort of network slowness. You have a monster of a machine, it should be able to handle a few trees. Im not a fan of XRefing in general - due to experience with slow render times, it became a personal preference.

 

VRay really hates some things - Opacity maps (especially on trees) is one of them. I wouldn't use XFrog Trees, nor would i use Onyx trees with Opacity Maps. They render slow, are more of a pain to render mattes of, and you can't get correct Z-depth passes with trees using opacity maps (it renders the plate, not the opacity mapped leaf)

 

so use onyx trees, but with geometry for leaves - it will look better and you get render elements - and mattes are easy. Again, drop them in as meshes, or vrayproxy them.

 

5. At the moment I'm using the demo version of Vray, (our licenses should arrive tomorrow) can I get it verified that the settings I make in the render setup resets every 5-10 minutes due to the demo version? Also, I cant use the distributed rendering with demo-licenses?

 

dont know, i don't use the demo version, im sure this will go away with the real licenses.

 

Cheers,

[Ricardo Eloy]

My 2 or 3 cents:

 

3- For exteriors, I have found rendering with VRayPhysicalCam+VRaySun+VRaySky (applied also as a map to a VRayLight dome) works like a charm. Tricky, but once you get used to it, it's a breeze.

4- Import the geometries and turn them into VRayProxies. You'll be able to render billions and billions of polygons without breaking a sweat.

5- The demo has these limitations, in fact. You can't keep your settings and won't have DR.