Thought I should do a quick tutorial on how I use these HDRi Skydomes I’m selling. Note that this is just one of many possible workflows, and there are probably lots of tricks I’m missing and even things I do completely wrong. I should also say that I work mostly with still images, not animations.

1. Here is a typical architectural scene. It is a model I made of Waro Kishi’s Fukaya house in Japan that never really went anywhere.

2. I use a gamma 2.2 workflow together with reinhard color mapping, so not strictly LWF but shares some of the advantages. I don’t want this to turn into a LWF tutorial or discussion, but this post on cgpov.com pretty much sums up how I feel a gamma corrected workflow helps us as visualisation artists.

The reinhard color mapping helps to control burnt out (overexposed) areas. Screenshot of my color mapping set up: The burn value of the reinhard color mapping typically ranges from .75 for an exterior to 0.05 for an interior. You need to experiment with the value until you gain control over the burnt out areas. Here is an example with a camera pointing at the HDR sky:

For the final render, I use the Vray Frame Buffer, and add a slight s-curve to the output to compensate for the lack of contrast that the gamma corrected workflow introduces:

3. Add a vray dome light and load the exr/hdr using the max bitmap loader. Set the mapping type to environment/spherical. If you are using .hdr files, you can use the vrayHDRi loader instead. It makes no difference whether you use the bitmap loader or the vrayHDRi loader, the vrayHDRi adds a bit more control in that you can control the render multiplier independently from the viewport multplier. Set the output of the .exr to 1 and the vraylight multiplier to 1. If your hdr/exr has no alpha channel it seems you can save quite a bit of memory while rendering (approx 200mb in my case) if you load the exr/hdr as realpixel float rgb rather than the rgba option.

[Click for original size]

4. To rotate the HDR you need to enter a U offset value from 0-1, so to rotate 180 degrees with would enter 0.5, 270 degrees 0.75 etc.

5. Add a vrayphysicalcamera, and set the aperture and shutter speed to something that would work for a typical outdoor scene, like F4, 1/200th & ISO 100. Remember that you are in effect using a completely manual camera, there is no ‘P’ or automatic mode so you need to experiment with different exposures until you get a good result.

[Click for original size]

6. Hit render and see what you get. If it looks too dark/bright I tend to adjust the bitmap’s output rather than the vraylight multiplier, so that I can have a couple of ready setup HDRi’s ready to drag and drop onto the dome light. In the examples below I use an output value of 1.5.

UPDATE: The slideshow below will automatically update as I add new HDRi skies.

Click image to zoom

Decided to finally start selling 3d models and HDR images. First up is my model of a chair by Paulo Mendes da Rocha. It’s such a cool chair, I really should use it more often in my own renders! If I sell enough of these I might be able to afford a real one.

I decided to go with 3DOcean.net as they seem to be more focused towards quality than other 3d assets sites. Here’s the link to my model: Paulistano on 3DOcean.net

(Should be high enough resolution to work well in fullscreen mode)

Everything in this scene was 3d, so making the day/cloudy/dusk shots was simply a case of changing the HDR used to light the scene, and turn on/off lights.

The Third & The Seventh from Alex Roman on Vimeo.

If you haven’t seen it already, make sure you check out Alex Roman’s short film The Third & The Seventh. Truly inspirational, and an incredible piece of work by just one person. His passion for architecture and photography shines through.

I’m on the judging panel for an exciting new architectural visualisation challenge on Ronen Bekerman’s blog. The challenge will be to render a house design by Dunsky Kornhauser Architects and runs from the 15 Dec 2009 to 15 March 2010. Ronen has managed to assemble a really impressive list of prizes. Looking forward to seeing the entries!

If you haven’t already bookmarked Ronen’s site then make sure you pay him a visit, so many good tips and tutorials.

As usual, the renders are more or less as they were directly from vray, just added some glows to the lights.

A tutorial on making leaf materials for 3d trees, in this case a sugar maple (in autumn).

Firstly, some observations on opacity mapped leaves vs. geometry leaves. As you can see in the image above, the images in this post were made using opacity mapped leaves. After some tests on my farnsworth house project, I have come to the conclusion that it is quicker in most cases to use opacity mapped leaves. Its true that in simple scenes trees with geometry leaves may render quicker as VRay doesnt have to calculate the opacity of thousands of leaves, but in dealing with complex scenes with millions of polygons the advantage in using (a lot) less RAM is huge. The processes involved in swapping opacity mapped plates for geometry are also very long winded and very tedious!

Exporting from Onyxtree. I went with 4 polygons per leaf so that the leaves aren’t just flat. Remember to set the dimensions you want the individual leaves, and change the units when you export. You can also make it export 3 different leaf IDs with varying sizes. I normally export as a .obj file.

Opacity mapping. It’s important to make sure the opacity map is just pure black or white, with a sharp edge. The opacity map I used can be found here (its not a great example!). You should also turn off filtering in the bitmap loader options (screenshot).

As imported to 3dsmax and given grey materials.

VRay2sidedMtl. The vray 2 sided material works best with geometry that has no thickness, which is what onyxtree outputs. It is a very quick way of generating a SSS (sub-surface scattering, think candle wax, skin, milk etc) type look. The image below is rendered using a vray2sidedmtl on all leaves with grey submaterials and a hand drawn image for the vein skeleton.

Front material. The front side material is a basic vraymaterial with a diffuse map and a reflection map. Click here for front vray material set up. The color correction map is to produce slightly different hues of leaf for each of the 3 sub leaf types (you should have got a mult-subobject material when you imported the .obj file). I usually make the first leaf and then copy and paste it to the 2nd and 3rd and just change the hue value slightly. The diffuse map looks like this, and the reflection map is a b&w copy with levels adjusted to make it more contrasty.

Render showing front leaf material on both sides with no transparency.

Back material. The back material is a copy of the front material but with a different diffuse bitmap and not quite as reflective. Note that I overlaid the veins skeleton jpg on top in photoshop as well. (without it, the veins looked too light when viewed from the underside as they took 100% of the lighter back material)

Render showing 2sided material with correct front/back materials but no transparency.

Finished result Click image for 800px version. Rendered using vrayphysicalsky and sun, and a vrayphysicalcamera.

UPDATE: .obj and .3ds added.