Virtual_photography_studio_V-Ray

In this tutorial you will learn how to set up a studio environment suited for rendering a highly detailed and reflective watch using 3ds Max, V-Ray and Photoshop. Using the newly added VRaySoftBox material, you can create various shapes and gradients directly inside 3ds Max as well as adjust the lights colour to simulate real world soft boxes that are commonly used in photography. HDRI dome lighting will also be used for additional direct lighting and reflection.

The VRayPhysicalCamera will be used to balance exposure and once the lighting and camera has been set up you will be taken through the steps of linear workflow. As well as how to adjust the V-Ray render settings for outputting render elements in EXR format to create a production level render. By using the EXR format, the final render has much more colour information that can then be tweaked in Photoshop without the risk of colour banding appearing.

In Photoshop you will combine each render element that makes up the beauty pass using a combination of blending modes. By keeping each element separate you are then able to tweak each one individually such as reflection, refraction and diffuse. Finally once the final image is complete you will learn how to down convert to an 8bit format so that the final render can be saved out for web use.

Software required

V-Ray 2.40.01, 3ds Max 2012 and Adobe Photoshop CS6.

Assets required

Linear RGB ICC profile
HDRI pack

Downloads

If you would like access to the scene files used in this tutorial please click here to download. Original watch model courtesy of Petr Mucka (Visuart3D).You can find a link to our video tutorial at the end of this post.

Creating a curved backdrop for the stage

Start by opening t_171_Max-Vray_Start.max and in the top viewport create a box and adjust the size to 400mm x 400mm x 400mm. Name the box Stage. Right click the move tool and set it to 0 for all axes in absolute world. Convert the Stage to an editable poly and select the lower back edge. Chamfer the edge by 100mm and set the segments to 50. Select the top, front and side faces and delete them so that you are left with a curved back drop.

Virtual_photography_studio_V-Ray_Fig01

Make the stage invisible to the camera but still contribute to lighting and reflection

Right click the Stage then go to object properties and under general un-tick visible to camera. This will make the stage not appear in the final render but still contribute to the scene so that lighting can bounce off it. Open the material editor, create a new V-Ray material and assign it to the stage. Set the diffuse colour to R1 G1 B1. Select the stage and make sure that the object’s colour is different to any colour used on the watch so that it can be easily selected in Photoshop.

Virtual_photography_studio_V-Ray_Fig02

Positioning the lights around the watch to highlight feature points

Under lights in the create panel, go to the VRayLight, turn on targeted and set the half-length and half-width to 150mm. Drag a plane light out in the viewport and with the light selected, right click the move tool and set X -5.8mm Y 13.345mm Z 407.078mm. Select the light target and set X -5.853mm Y 13.345mm Z 186.568mm. Name the light Top Light. Turn on invisible so that the light is not seen in the render and increase the shadow subdivisions to 32 to reduce noise in shadowed areas.

Virtual_photography_studio_V-Ray_Fig03

Create a copy of the light and name it Key Light. Position the light in absolute world X -5.853mm Y -193.52mm Z 304.437mm. Increase the multiplier of this light to 100. Create a third copy of the light and name it Low Light. Position the light in absolute world X -39.759mm Y -38.818mm Z 58.616mm. Select the light target and position it in absolute world X -3.063mm Y 24.74mm Z 186.568mm. Set the multiplier to 50 and change the half-length to 350mm and the half-width to 100mm.

Virtual_photography_studio_V-Ray_Fig04

Create detailed lights and reflectors with gradients using the Softbox texture

Open the slate material editor and drag a new VRaySoftBox texture onto the slate and name it Softbox. Set the base colour to R150 G150 B150 then under Hot Spot / Dark Spot tick on and set the outer radius to 0.6.

Virtual_photography_studio_V-Ray_Fig05

Load grid files to generate gradients ramps

Go to frame and turn it on. Right click the gradient and choose load, then locate Frame.grd from the assets folder. The grid file tells V-Ray where to put a marker on the gradient ramp and what colour that marker should be. This particular grid file creates a thin black frame around the soft box. Alternatively you can create your own by manually clicking inside the gradient box. These can also be loaded into other gradients and Softbox materials.

Virtual_photography_studio_V-Ray_Fig06

Increase the resolution of the Softbox texture to improve the light and reflections

Drag and drop the softbox texture into the texture slot of all the lights and choose instance. Set the resolution to the maximum of 2048. The higher the resolution the more samples are generated for brighter areas of the texture which improves the lighting and reflection.

Virtual_photography_studio_V-Ray_Fig07

Additional Softbox textures available to download

Add further variation to your studio lighting setup and experiment using our collection of light shapes. Click here to go to download page.

VRaySoftBox_Lights

Add additional direct lighting and reflection using the VRay Dome Light and HDRI

Currently the light is only coming from three main sources. This means some parts of the watch will not receive any light or reflection. To fix this a VRay Dome Light can be used together with a HDRI image to fill in those gaps using a technique called image based lighting (IBL).

The V-Ray Dome Light uses importance sampling to improve lighting, shadow and reflection

The dome light is a direct light that uses importance sampling to trace where the bright areas of the HDRI are so that it knows where is best to apply more samples. Compared to just adding a HDRI in the environment slot this is a much better solution as it gives fast and clean results.

Add a VRayLight into the scene and set the type to Dome and turn off targeted. It doesn’t matter where the light is placed as long as it is perpendicular to the ground plane and rotating the light does not affect the texture position, this is controlled via the parameters of the HDRI map. Set the multiplier to 30 and make sure invisible is ticked otherwise you will see the HDRI image in the background.

Virtual_photography_studio_V-Ray_Fig08

Use spherical HDRI images to generate an image based lighting environment

Under texture assign a VRayHDRI map and set the resolution to 2048. Drag the VRayHDRI over to the slate material editor, choose instance and name it Dome HDRI. Browse to the assets folder and choose 07.HDR. Set the mapping type to spherical so that the HDRI texture is mapped correctly to the dome shape. Then tick flip horizontally so that it is facing the right way inside the dome.

Virtual_photography_studio_V-Ray_Fig09

Positioning the camera and setting exposure

Under the create panel in cameras, select VRay from the drop down list and add a VRayPhysicalCamera to the scene. Position the camera in absolute world X -3.917mm Y -230.287mm Z 45.287mm. Then position the camera target X -3.344mm Y 21.12mm Z 177.367mm.

By adjusting the f-number and film speed you can match the intensity of the lights to avoid being over or under exposed

Set the film gate to 20.5mm and the focal length to 40mm. Lower the f-number to 5 and film speed (ISO) to 60. Turn vignetting off to remove the darkened edges effect and set the white balance to neutral. Any colour adjustments will be done in post-production so it is best to start with an image that has a neutral white balance.

Virtual_photography_studio_V-Ray_Fig10

Adjusting the V-Ray render settings for linear output and final production

Go to the render setup, in the V-Ray tab under image sampler (antialiasing) set the antialiasing filter to quadratic. This is a blurring filter that helps reduce unwanted harsh edges between objects. These harsh edges usually occur when a pixel is brighter compared to the neighbouring pixels and can be fixed by either using a blurring filter or clamping the colour to reduce the brightness.

Improving antialiasing between contrasting pixels

In the adaptive DMC image sampler, increase the min subdivisions to 2 and the max to 6. This will improve the antialiasing and reduce noise.

Virtual_photography_studio_V-Ray_Fig11

Set the gamma to 2.2 and turn on don’t affect colours (adaptation only). With this on V-Ray will do all the calculations using gamma 2.2 but it will not burn this into the final image. This allows the final render elements to be linear so that when compositing they blend together correctly. Under colour mapping, turn on both sub pixel mapping and clamp output. Set the clamp level to 3 and turn off affect background. Turning on clamp output will reduce render times but at the cost of reducing flexibility for tweaking in post.

Virtual_photography_studio_V-Ray_Fig12

Improve the quality of the global illumination render element by using higher subdivisions in the irradiance map

Turn on indirect illumination and set the secondary GI engine to light cache. Under irradiance map set the preset to medium and set both the HSph subdivisions and the Interp. Samples to 150. This will improve the quality of the global illumination and reduce splotches. Turn on show calculation phase to see the results during rendering.

Virtual_photography_studio_V-Ray_Fig13

Under light cache increase the subdivisions to 1500 and set the number of passes to match the number of processing cores you have available. Turn on show calculation phase. In the reconstruction parameters tick use light cache for glossy rays. With this option on, the light cache will be used to calculate glossy rays as well as normal GI rays which can greatly improve render time.

Go to the render elements tab and add the following render elements

VRayWireColor
VRayGlobalIllumination
VRayLighting
VRaySpecular
VRayReflection
VRayExtraTex
VRayBackground

There is no need to add a refraction element as transparency will be included in all the other elements with the glass material being set to all channels in the refraction. The wire colour element is useful for completing post production work. It takes the wire colour of the object in 3ds Max and renders out a flat diffuse colour that can be easily selected in Photoshop. This element also has antialiasing so you get the blurred edges from the AA filter.

In the VRayBackground parameters, un-tick colour mapping so that the background image is not affected and remains the same brightness and colour.

Ambient occlusion brings back shadow detail that is lost during rendering

One of the render passes to include is ambient occlusion and by incorporating it into a render element it is much more efficient and there is no need to turn lights off or hide transparent objects which is a requirement in some other methods. Select the VRayExtraTex element and add a VRayDirt map to the texture slot. Drag the VRayDirt map to the material editor and choose instance. Set the radius to 50mm, the subdivs to 18 and turn on work with transparency. The radius size depends on the scene, the larger the radius, the larger the dirt will spread. So if the radius is too large for a small object then the size of the ambient occlusion will become too much. The mode is set to ambient occlusion by default. Click exclude and from the list select Watch Glass and move it over the exclude box on the right.

Virtual_photography_studio_V-Ray_Fig14

What to do when working with transparent materials and ambient occlusion

In order for ambient occlusion to render successfully the refraction of the glass material must be set to affect all channels otherwise the ambient occlusion will not go beyond the glass.

Enable the V-Ray Frame Buffer

Go to the V-Ray tab and under V-Ray enable the built-in Frame Buffer and un-tick get resolution from Max. Set the width to 5000 and the height to 3750. Tick save separate render channels and un-tick save alpha as this will automatically be included in the output file. Click browse and locate to a folder to store all the render elements. Select OpenEXR from the save as type drop down list and in the EXR make sure it is set to Half Float (16bits/channel). Half float has enough colour range for compositing so there is no need to render in full float unless it is specifically required for passes such as Z-Depth where full float would be useful.

In environment and effects, add Chrome_Background.tif as a background environment map. Now click render and in the VRay Frame Buffer, turn on show sRGB to view the render at the correct gamma. This gamma correction will automatically be applied when opening the EXR files.

Compositing the render elements in Adobe Photoshop

Close the image and go to file then scripts and then load all the files into stack. Browse to the renders folder and select all the render elements. When prompted, choose as alpha channel and click OK. If you are not prompted and the layers open with transparency, you need to first open an individual layer and choose as alpha channel to set it as the default.

Once they have loaded into the layers stack, move VRaybackground to the bottom. Then move VRayWireColor, RGB Color and VRayExtraTex to the top and turn them off.

Virtual_photography_studio_V-Ray_Fig15

Linear Dodge (Add) blends each layer by increasing the brightness of the colours from the layer below

Select the VRayReflection, VRaySpecular, VRayLighting and VRayGlobalIllumination layers and set the blend mode to Linear Dodge (Add). Check the final composite is correct by turning on the RGB layer to make sure they match.

Virtual_photography_studio_V-Ray_Fig16

Converting from 32 bit to 16 bit

Photoshop opens 16 bit half float as 32 bits per channel and the editing tools do not work at this level. In order to carry out any post editing, the file needs to be down converted to 16 bits per channel but in doing so causes all the blending modes to be incorrect resulting in a blown out image.

To fix this you need to assign a linear colour profile in Photoshop before converting. Courtesy of VFX FORGE, in the assets folder, copy the Linear RGB ICC profile to C:\Windows\System32\spool\drivers\color. Then in Photoshop go to edit and then colour settings. By default the working space is set to monitor RGB – sRGB IEC61966-2.1 and because we composited in linear we need to change that to match. In the RGB drop down list choose load RGB and browse to where you copied over the Linear RGB ICC profile and click OK.

Virtual_photography_studio_V-Ray_Fig17

Now go to image, mode then 16 bits/channel and choose don’t merge when prompted. You may notice that your render has some colour banding but this is not part of the image, this is Photoshop not being able to display it properly when zoomed out. If you zoom in 100% you will see the correct image.

Virtual_photography_studio_V-Ray_Fig18

Post production techniques

Before you do any adjustments such as levels or colour correcting you need to revert back to Monitor RGB sRGB IEC61966-2.1, otherwise any adjustments you make will be using the wrong colour setting. Go to edit and then colour settings to change it back to sRGB IEC61966-2.1.

Editing the Photoshop file after closing

To edit the Photoshop file after you have closed it you first must load the Linear RGB ICC profile and then open the PSD file. Once open you can revert back to sRGB IEC61966-2.1.

Lower the opacity of the ambient occlusion to avoid making the image appear unrealistic

Turn on and select the VRayExtraTex layer which is the ambient occlusion. Marquee select the outer black area and remove it otherwise it will affect the background layer. Set the blend mode to multiply and you will notice shadow details will appear that were lost during rendering. Set the opacity to around 50% as sometimes too much ambient occlusion can make the render look unrealistic.

Virtual_photography_studio_V-Ray_Fig19

Add in colour correction to give a metallic feel to the watch

Select all the layers in the stack apart from the background layer and convert them to a smart object. This allows you to still edit the stack later on if you need to by double clicking on the smart object to open it. Set the smart object blend mode to Linear Dodge (Add). Add a colour balance adjustment on top and make it only affect the smart object. To do this hold Ctrl + Alt and click between the adjustment and smart object layers. Set the cyan – red to -5 and the magenta – green to +2.

Virtual_photography_studio_V-Ray_Fig20

Use HDR toning to down convert a 32 bit composite to an 8 bit format

If you down convert to 8 bit from 16 bit you will notice colour banding in the image. In order to successfully save out an 8 bit image that can be used for web, first up convert to 32 bit and choose rasterize and then merge. There is no need to switch colour profiles to do this so make sure you are still using sRGB IEC61966-2.1.

Now go to image then mode and choose 8 bit. Choose merge and a HDR toning window will appear. In the method drop down list choose Exposure and Gamma and click OK without adjusting any of the settings. You can now save out the final render in an 8 bit format.

Virtual_photography_studio_V-Ray_Fig21

Workflow techniques

Use V-Ray RT for real time feedback

When you are setting up the lighting for the studio, V-Ray RT gives you real time feedback so you can easily tweak light intensity to match the camera exposure. As V-Ray RT is fully interactive you can move around in the camera view to see how the materials react to the lighting to get those all-important highlights.

Virtual_photography_studio_V-Ray_Fig22

The resulting render in V-Ray RT is an accurate representation of the final production render. It is a very fast rendering tool for previewing the final render result. Use the draw region tool so that only the drawn area will update in the RT window. This will provide even faster feedback particularly when in heavier scenes that might cause RT to slow down.

Virtual_photography_studio_V-Ray_Fig23

You can pause RT to continue working without it updating as you move around in the viewport. This is useful if you have a complex material that needs time to be clear of noise.

Virtual_photography_studio_V-Ray_Fig24

Avoiding unwanted edge halos

Edge halos and jagged edges are a common issue when choosing to render with transparent backgrounds. Some of the common causes are sharpening AA filters and over bright pixels. This tutorial uses a method where by the background is included as a render element. When composited, it doesn’t show a halo or jagged edges and it blends correctly because the area where the watch is positioned is made black.

Virtual_photography_studio_V-Ray_Fig25

Without the background layer, you would have to generate an alpha mask to mask out the background in post-production. Every time a render element blends with another it increases the edge halo effect and the alpha mask doesn’t quite line up to remove it. As a result you have to use matting tools such as remove black matte or defringe which doesn’t always give you a clean edge.

In addition, colour clamping also helps as you are reducing the amount of dynamic range and it will also improve render times. A higher clamp level can also lead to aliasing so to counteract this, the blurring filter is used.

Watch the video tutorial