Guide To Creating A Virtual Photo Studio

Hi there,

Here James Cutler, a creative director, shares tips to use elements of V-Ray and 3ds Max for creating a photographic studio in the digital world.

This tutorial will guide you how a studio environment is set up to render a reflective and detailed watch by V-Ray and 3ds Max.

Step 1 – Creating the stage

Open t_171_Max-Vray_Start.max from the files provided with this tutorial. Then create a box in top viewport, adjusting its size to 400mm x 400mm x 400mm and name it Stage.

Right-click on the Move tool and in Absolute World set a value of 0 for its all axes. Next we will convert Stage box into an editable poly, by selecting the lower back edge. The edge is to be Chamfered by 100mm and the segment is to be set to 50. By selecting the front, side and top faces, delete them and you will have a curved backdrop.

Right click on the Stage and go to Object Properties. Now un-tick the Visible To Camera option under General. This is important so that Stage will not be visible in final render; however it will still be crucial for the scene by making the light which you have set up to bounce off. To create a V-Ray material, open Material Editor, and then assign it to Stage. The diffuse colour should be set to R1 G1 B1.

Now, while selecting Stage ensure that the colour of the object is not same as the colours which have been used on watch. This will help in selecting it in Photoshop easily.

Step 2 – Light positioning

Go to VRayLight under Lights option, which is present in Create Panel. Targeted should be turned on, while the Half-width and Half-length should be set to 150mm. Next a plane light should be dragged out in viewport. By selecting the light, right click on Move tool. Now set these values, X to -5.8mm, Y to 13.345mm and Z to 407.078mm.

The select light target while setting X to -5.583mm, Y to 3.345mm and Z to 186.568mm and name it Top Light. Invisible should be turned on, as it will ensure that light is not visible in render. Now the Shadow Subdivisions should be increased to 32.

Create a copy of light and it should be named Key Light. While positioning the light in Absolute World, set X to -5.853mm, Y to -193.52mm and Z to 304.437mm. The multiplie of this light should be increased to 100. Create another third copy of light, Low Light. Now Setting up the light in Absolute World, set X to -39.759mm, Y to 38.818mm and Z to 58.616mm.

Now make a selection of light target, while positioning it in Absolute World, set X to -3.063mm, Y to 24.74mm and Z to 186.568mm. Multiplier should be set to 5, while changing 100mm as Hafl-width and 350mm as Half-length.

Step 3 – Using VRaySoftbox material for stimulating real soft boxes

By opening Slate Material Editor, drag new VRaySoftBox texture on slate, naming it Softbox. Base colour should be set to R 150 G 150 B 150. Now tick On under Hot Spot/Dark Spot and Outer Radius should be set to 0.6.

Now turn on the Frame. Choose Load by right clicking the gradient and from Assets folder locate Frame.grd.

The grid file helps to tell V-Ray the location of market on gradient ramp, as well as the colour of marker. A thin black frame will be created by the specific grid file around soft box. On the other hand it can also be created manually by clicking in the gradient box. It is also possible to load these in other softbox materials and gradients.

Select Instance after dragging and dropping softbox texture in texture slot of all lights. The resolution should be set maximum to 2048. Remember, higher resolution means generation of more samples for brighter areas of texture, which enhances reflection and lighting.

Step 4 – Adding additional direct lighting

Right now the light will come from three prime sources and it implies that there will be no reflection or light on some parts of watch. You can use V-Ray Dome Light along with an HDR image for fixing this and filling the gaps. The technique used is called IBL or Image Based Lighting.

Done Light is direct light which makes use of importance sampling for tracing where the HDR image’s bright lights are. It helps it know where the samples should be applied. This is considered a better solution, offering faster and cleaner results, as compared to the addition of HDR image in environment slot.

Next step is the addition of VRay Light into scene, setting Dome as type and turning off Targeted. The positioning of light will not matter if it is perpendicular to ground plane and when the light it is rotated it does not have any effect on texture position and all this is controlled through the HDRI map’s parameters. Multiplier should be set to 30 and Invisible should be ticked. If it is not done then HDR image will be visible in background.

In Texture option, assign a VRayHDRI map, while the Resolution should be set to 2048. Drag VRayHDRI to Slate Material Editor, select Instance, while naming it Done HDRI. Now it is time for the HDR image to be loaded. Mapping type should be set to Spherical, to ensure that HDRI texture is correctly mapped to dome shape B. Now select Flip Horizontally, to make it face right way while in the dome.

Step 5 – Camera positioning and exposure set up

Select VRay which will appear in drop down list under Control Panel in Cameras and a VRayPhysicalCamera should be added to the scene. The camera is to be positioned in Absolute World and set X to -3.917mm, Y to -230.287mm and Z to 45.287mm. The Camera Target should be positioned to X to -3.344mm, Y to 21.12mm and Z to 177.367mm. Film Gate is to be set to 20.5mm and 40mm as Focal Length, f-number should be lowered to 5, while film speed to 60.

For removing the effect of darkened edges turn the Vignetting off, while setting Neutral as White Balance. As colour adjustments, if any required, are only possible in post-production, thus it is better to use an image with neutral white balance to get started.

Step 6 – Adjustment of render settings of V-Ray

Open Render Setup. Under Image Sampler, there is V-Ray tab. Select Quadraric in the place of Antialiasing Filter. This blurring filter is aimed at reducing sharp edges which are not required between objects. This usually occurs in case the brightness of one pixel is more than its corresponding pixels. To rectify it either a blurring filter can be used or colour can be clamped for reducing brightness.

Now move on to adaptive DMC Image Sampler, where the value of Min Subdivisions should be increased to 2 and 6 for Max Subdivisions. This will help in improving antialiasing, while reducing noise. Clamp Output and Sub-Pixel Mapping, under Mapping, should be turned on. Clamp level should be set to 3, while Affect Background is turned off.

Gamma is to be set to 2.2, while Don’t Affect Colours should be turned on. This ensures that all the calculations by V-Ray will be done with Gamma 2.2. However, this will avoid it from burning in final image. This also facilitates the final render elements are linear. So they can correctly blend together, while compositing.

Indirect Illumination should be turned on, while the secondary GI engine should be set to Light Cache. Preset under Irradiance Map should be set to Medium, while the value of both Interp Samples and HSph Subdivisions should be 150. Along with improving the global illumination quality, it also reduces splotches. To view the results during rendering, the Show Calculation Phase should be turned on.

The Subdivisions setting under Light Cache should be increased to 1500, while the number of passes should match the available number of processing cores. Show calculation phase should be turned on. Tick Use Light Cache for Glossy Rays in Reconstruction parameters. While this option is turned on, use light cache for calculating both glossy rays and normal GI rays. It can improve render time greatly. The render elements mentioned next are to be added in the Render Elements tab – tab and add the following render elements: VRayGlobalIllumination, VRayWireColor, VRayLighting, VRayReflection, VRayExtraTex, VRaySpecular, and VRayBackground.

Adding a refraction element is not required. In every element transparency can be included by setting the glass material in Refraction to All Channels. In post-production work wire colour element is very useful. An object’s wire colour can be taken in 3ds Max and a flat diffuse colour can be rendered out by easily selecting it in Photoshop. As antialiasing is present in this element as well, thus the blurred edges can be obtained from AA filter.

Uncheck Colour Mapping in VRay Background parameters. It will ensure that the background image does not get affected and maintains the same colour and brightness. Another render pass required to be included is Ambient Occlusion. It can prove very efficient, if you can render it into another element. Also unlike other methods where the transparent objects are required to be hidden or lights need to be turned off, these are not needed in this.

Now a VRayDirt map should be added to texture slot which can be done by selecting VRayExtraTex element. VRayDirt map should be dragged to Material Editor and select Instance. 50mm should be the Radius, 18 is the Subdivs. Work With Transparency option should be turned on. The size of radius should be according to scene – larger radius means that the dirt will also spread to larger area. It means if radius for a small object is too large then the ambient occlusion’s size will also be a lot. By default Ambient Occlusion should be set as mode. Choose Watch Glass from the list which appears by clicking Exclude, and it should be moved onto the right over to Exclude box.

In V-Ray tab, the in built Frame Buffer should be enabled, while Get Resolution From Max should be un-ticked. Height should be set at 3750, while width at 5000. Save Alpha is to be un-ticked, while tick the Save Separate Render Channels. Now a folder should be located for storing all render elements. From the drop down of Save As Type, select Open EXR. Further in this option, the Half float should be set.

The colour range in Half Float is enough for compositing, thus you are not required to render in Full Float, until unless you need it for passes, like Z-Depth. Chrome_Background.tif should be added as background environment map in Environment and Effects. Click on Render and Show RGB should be turned on in VRay Frame Buffer for viewing render at the right gamma. The gamma correction you make here will be applied automatically while you open the EXR files.

Step 7 – Compositing of render elements in Photoshop

After closing the image, go to Scripts in File menu and here all the files should be loaded in stack. Go into the Renders folder to make a selection of all render elements. When the option appears, you should select As Alpha Channel and click on OK. In case the option does not appear and the layers start opening with transparency, then an individual layer should be opened first and then select As Alpha Channel as default.

Once the loading of render elements in layers stack is done, VRay Background should be moved to the stack’s bottom. After moving VRay WireColor, VRay ExtraTex and RGB Color to top, these can be turned off.

Blend mode should be set to Linear Dodge (Add), after selecting VRay Reflection, VRayLighting, VRaySpecular and VRayGlobalIllumination layers. You need to check if the final composite is right and to do this you can turn on RGB layer to ensure that they match.

Step 8 – To convert 16-bit from 32-bit in Photoshop

Photoshop will open 16-bit Half Float as 32 bits per channel and at this level; you will not be able to use editing tools. You need to down convert the file to 16 bits per channel; however it will make all blending modes incorrect, which will then result in a blown out image. This can be fixed by assigning a profile of linear colour before conversion takes place. A suitable profile is offered by VFXForge.

Copy Linear RGH ICC profile to C:WindowsSystem32spooldrvierscolor, in assets folder. Then in the Edit menu, go to Colour Settings. The work space is by default set to Monitor RGB sRGB IEC61966-2.1: It is needed to be changed for matching, as it was composited in Linear. Select Load RGB in RGB drop down menu, and mover to Linear RGB ICC profile.

After clicking OK, select Image > Mode > 16 bits/channel and when the option appears, select Don’t Merge. Here some colour banding may occur. This is because the image cannot be properly displayed by Photoshop when it is zoomed out. The correct image can be viewed by zooming in.

Step 9 – Techniques for Post Production

Prior to making any adjustments in colour correction or levels, you are required to revert back to Monitor RGB sRGB IEC61966-2.1. If it is not done, then wrong colour settings will be used in any adjustments made by you. For changing it back to sRGB IEC61966-2.1, you should select Colour Settings in Edit menu.

VRayExtraTex Layer should be selected next after turning it on, as it is the ambient occlusion data. Select outer black area with Marquee for removing it. If you do not remove it, then it can affect your background layer. Blend mode should be set to Multiply. Once it is done you will notice the shadow details appearing, which were earlier not visible during rendering.

The Opacity should be set to 50%. At times a lot of ambient occlusion can give an unrealistic look to the render. All the layers present in stack should be selected, except background layer and these should be converted to a Smart Object. This will make it possible for you to edit the stack in future, if needed and this can be done by opening Smart Object with a double click.

Linear Dodge (Add) should be set as blend mode of Smart Object. On top a Colour Balance adjustment should be added, to make it impact only the smart object. The magenta-green should be set to 2, while cyan-red to -5.

Step 10 – Conversion of Layered PSD file into 8-bit Image Format

Some colour banding might appear in image, in case 16-bit is down converted to 8-bit. To save an 8-bit image successfully and make it usable for web later, firstly it should be up converted to 32-bit and then select Rasterize and Merge. Ensure that you are making use of sRGB IEC61966-2.1, as switching of colour profiles is not required for doing this.

Now select 8-bit as Mode in Image menu. When you will select Merge, an HDR toning window will open. Select Exposure and Gamma in the drop down list named Method and press OK. Remember there is no need to adjust the settings. The final render can now be saved in 8-bit format and it is ready to be used for web.

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