Converting an Interior Scene to C4DtoA

Rollover image for wireframe

 

This tutorial is a breakdown of the workflow required to convert an interior scene that has been setup for another renderer for rendering with Arnold. Scene setup and rendering should take no longer than an hour. The scene used in this example is part of   of architectural interiors.this collection

The scene has been exported from 3ds Max as an .fbx file and imported using the FBX plugin.

The workflow covers the following topics:

Lighting

Shading

Render Settings

 

Lighting 

The scene is lit very simply with  lights positioned outside of the windows of the room. The c  has been set to that of daylight quad olor_temperature. Leave the default light samples setting at 1. For final rendering, increase this value to 4 to reduce any noise in the shadows.(5500)  

Increase the   of the light to around 20.exposure

Use a   to simulate sunlight coming through the far window. Increase the   slightly to around 0.2. This will give the sunlight a directional_light anglesofter edge to the shadow on the floor. You may need to increase the samples of the   if you do (3 should directional_light (distantant_light)  suffice). Enable   and choose a slightly warmer temperature like 5000.color_temperature

Scene lit with Quad lights outside of the windows and a Directional light representing sunlight

Another tutorial that demonstrates different ways to approach lighting a room can be found here.

To preview how the lighting will affect the scene, you can apply a (reduce to 0) shader override to the scene. standard_surface specular_weightThis effectively creates a 'chalk preview' of your render and allows you to focus purely on lighting without being concerned about shading.

Shading

Floor Shader

Connect the diffuse color map to the  of a shader.base_color  standard_surfaceConnect the bump map to the  attribute. Reduce the  to a small amount like 0.03.bump bump_depthIncrease the   to 0.3 and increase the  to 0.2 to give the floor a glossy appearance.specular_weight   specular_roughnes  

Mirror

Assign a shader to the mirror and rename it 'Mirror'.standard_surfaceReduce the   to 0.base_weightIncrease the   to 1.metalnessReduce the tospecular_roughness 0.

Curtain

Here, we will use  and  to thin_walled subsurface provide the effect of translucency with the curtain being lit from behind.

Assign a shader to the curtain and rename it 'curtain'.standard_surfaceEnable (Geometry).thin_walledIncrease the  to around 0.5.subsurface_weight

Reducing the to 0 will disable indirect lighting. This is useful when you want to test render direct lighting in the scene diffuse_samples  effectively and will also be quicker to render.

: 0 (disables indirect lighting)diffuse_samples

Information about can be found .specular_fresnel here

Rollover image to see the effect of translucency on the curtain

Glass Door

Assign a to the glass door and rename it 'Glass'.standard_surfaceReduce the   to 0.base_weightIncrease the   to 1.specular_weightIncrease   to 1 (this makes the glass transparent).transmission_weightIncrease the index of refraction  to 1.5 (glass).(IOR)You can also add a tint to the glass very easily by adding a subtle hue to the transmission_color.

 

Render Settings

Sampling

For the final render, the   settings were increased to 6. Camera (AA)The   were also increased to 6 to reduce noise in indirectly lit areas of the room. The images below show the difference between diffuse_samples  rendering 2 (default) and 6.diffuse_samples

Ensure that the polygon face normals are all facing in the right direction (especially important when rendering glass surfaces with Arnold). 

Rollover image to see difference between 2 and 6 diffuse_samples

Ray Depth

Diffuse Ray Depth

The images below were rendered using a  of 1 4 You can notice a clear difference of bounced light around diffuse_ray_depth (default) and   (rollover image).  the curtain for example.

Rollover image to see difference between 1 (default) and 4diffuse_ray_depth

Care should be taken when increasing this value as your render times will increase dramatically.

More information and tutorials about removing noise can be found .here

Transmission Ray Depth

You can 'clearly' see the difference in the glass vases when increasing the in the images below.transmission_ray_depth

2 4 8

 

That concludes this tutorial on converting an interior scene for rendering with Arnold. 

Note that render times will linearly increase with regards to the number of ray diffuse bounces and therefore care should be taken when increasing this value.

More information about rendering glass surfaces can be found .here