Tutorials
General Application Specific Tutorials:
Please note that I am only providing a Vray-related HDR tutorial on this website. For other applications and HDR usage, please consult your product manuals and documentation, perform an Internet search, or inquire within product-related forums.
A Basic Vray HDR Tutorial:
I am going to outline a few easy steps for using High Dynamic Range Images with Vray 1.5 SP3 and 3dsMax. This should apply to any HDRs you may have in your texture and lighting libraries. Most of you are probably already aware of most of these basic steps but for those that don’t, I will try to walk you from the beginning without going into too much detail and theory.
1) First, you will want to use Linear Workflow for more accurate color reproduction. Technically, you do not have to use LWF but you will often find yourself manually adjusting your images in post-production in order to get them to look realistic. This is true regardless of any scene using Vray. You will want to open up Max and browse to the top menu bar: \Customize\Preferences\Gamma and LUT\ and set the following parameters:
01. Linear Workflow Settings.
2) It’s generally good practice to set your scene dimensions to real world units. Again, this is not necessary but it is very helpful for reproducing more accurate lighting conditions as well as working with both architectural and product models. I almost always try to approximate the dimensions of my models even if the measurements aren’t completely accurate. It is a very good habit to get into. Browse to: \Customize\Units Setup\ and set your parameters (I often use US Standard because I work with many US-based architects):
02. Units Setup.
3) Insert your model into the scene or create a new item such as a teapot in the top viewport. I’ll set the teapot radius to 1′ as an example.
4) Right click your model, select move from the context menu, and zero out the coordinates in the XYZ boxes at the bottom of your screen so this way your model is perfectly centered. Again, this isn’t necessary but it’s? just a good habit if you’re a modeler.
5) Create a plane in the top viewport near the center of the scene. Usually, I start to drag out the object as I’m holding the control button down — this way the plane is created from the center instead of an edge. I usually zero out all of my objects. Your scene should look something like this:
03. Scene setup.
6) VRay works best if you use Vray materials instead of standard ones. On larger scenes, it can easily shave off several minutes of rendering time. I always avoid non-Vray materials whenever possible. Create a plain white Vray Material and apply it to the plane. Please note with LWF, pure white colors can cause extremely long render times. I usually reduce my white values by several points out of habit. In this case I’m setting it to 254:
04. White Vray Material.
7) Create another Vray material of your choice. For this example, I’m going to use a basic chrome type of material as it will show some good reflections and apply it to your model/teapot:
05. Vray Chrome Material.
8) Create a VrayPhysicalCam in your scene like below:
06. VRayPhysicalCam.
Hit ‘c’ after laying out your camera in order to view the scene as the camera sees it. You may want to adjust the position of your camera with the rotation controls in the lower right-hand side of your screen. My Physical Camera settings for my files usually render nicely at F1.2. Sometimes I also set the White Balance settings to neutral.
9) Now we will set up the HDR lighting. There’s several ways to insert a HDR into a scene, but Vray provides a very efficient light (from a speed and sampling/noise reduction standpoint) called a domelight. This light can be inserted anywhere in your scene (position does not matter.) Occasionally upon inserting a light into a scene, the colors in the viewport will shift because the default Max lighting changes — just hit ‘ctrl+l’ several times in a viewport to change the default lighting setup in the viewports until you find something you can work with again.
Here is my HDR lighting setup:
07. VRayHDRI Setup.
Note that there is a resolution number which defaults to 512 under the Texture section of your light. This number can be dialed up or down (I used 1024 here) depending on the quality you desire. But it also adds rendering time. You can also choose ‘Spherical (full dome)’ under your light’s ‘Dome light options’ (not shown/cut-off above) if you want the light to completely encompass the scene from an angle below the horizon (the reason why this option is there is because it adds rendering time and not everyone is going to always see that portion.)
10) Drag the VrayLight VrayHDRI material over to an empty slot on your material editor (shortcut = m) and select ‘instance’ on the pop-up window. In the material editor, browse to the HDR/EXR of your choice:
08. HDR selection.
I chose a HDR from one of my own libraries which I created. My HDRs fit Spherical Mapping. You can usually tell which mapping type you have by looking at the little material preview window. If the image looks distorted, try the other type of mapping images.
11) Now we are ready to run a test rendering. Open up your rendering setup window from the top menu bar: \Rendering\Render Setup…\ (shortcut =F10.) I’ve provided a very efficient test rendering setup below:
09. VRay Test Rendering Settings.
12) Select your Camera in the viewport or hit the ‘c’ key after selecting your viewport if it isn’t already. This should switch you to your camera view. Now you are ready to make your first rendering test. Hit ‘render.’ Here is my result using my test settings and default camera values:
10. Test rendering output.
13) The scene may look perfect, too dark, or too bright depending on the HDR used. There’s several different options you have at this point. You can always change the camera angle, change the F-Stop (F Number) of the camera (lower number for a brighter scene and vice-versa), or adjust the brightness and contrast in post with a program like Photoshop. Also note that you may have vignetting turned on in the camera which may darken the image corners. And last but not least is your camera White Balance which may lend your image a certain tint. I usually turn mine to neutral but sometimes the daylight settings (default) works well.
14) As an alternate option, sometimes I add a Vraylight set to sphere, No Decay checked on, and slightly tinted yellow to my scenes in direct position of the sun. This will sometimes add a more defined shadow as well as a little bit more overall tint to your scenes. You may have to dial up and down your light multiplier. This is really dependent on the HDR being used as well as the look you are going for. In the image above, my teapot is in the shade (just like the HDR which was shot) and I’m fine with the lighting. I might dial down the F-Number of the camera .5−1.0 to make it a little bit brighter.
15) At this point, you can try out as many HDRs as you like by simply loading them in the Material editor. Also note you can change the camera angle manually, or turn the actual HDR by entering in new ‘Horiz. rotation’ values in the Material slot.
16) When you are ready to render the final image, adjust the ‘Width’ and ‘Output’ size under the ‘Common’ render tab to your liking. You may want to turn on the ‘Antialiasing filter’ under the ‘Vray’ render tab for sharper edges. Under the ‘Indirect Illumination’ tab, you can change your ‘Primary Bounces’ to ‘Brute Force’ (leave default) or ‘Irradiance Map’ (change to medium or high settings) and set your ‘Light Cache’ to around 1500 ‘Subdivs.’ Last but not least, under the ‘Settings’ tab, you can dial up the ‘Global subdivs multiplier’ to something like 2 or 3 (even higher) if you want to increase the overall rendering settings. Please note that all of these settings will increase rendering times as well as quality.
