2D cel and cartoon effects can easily be achieved with the V-Ray Toon Material. Use this material to make your scene get that hand-drawn look. Controlling the shadows and lights received by the material in combination with material transparency, gotten from Object or Material IDs, allows for fine-tuning the result. You can take advantage from the other standard V-Ray material options such as reflection, refraction, anisotropy, subsurface scattering and bump/normal mapping to set up the render to your liking.

The Diffuse/Specular Ramps controls the diffuse/specular color based on the amount of light received. Position 0.0 maps to light intensity 0.0, position 1.0 maps to light intensity 1.0 and above. See the Diffuse Ramp example below.

Color – Base texture blended with the color from the diffuse ramp. See the Diffuse Color with Diffuses Ramp example below.

Roughness – Used to simulate rough surfaces or surfaces covered with dust (for example, skin, or the surface of the Moon).

Roughness Model – Specifies the Roughness model.

Oren-Nayar – A reflectivity model for diffuse reflection from rough surfaces that has been shown to accurately predict the appearance of a wide range of natural surfaces. We recommend using this roughness model.
Gamma Based – The roughness model used in previous versions of V-Ray. This is not the recommended option.

Opacity – Assigns opacity to the material where 1.0 is completely opaque and 0.0 is completely transparent.

Opacity Mode – Controls how the opacity map works.

Normal – The opacity map is evaluated as normal: the surface lighting is computed and the ray is continued for the transparent effect. The opacity texture is filtered as normal.
Clip – The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode, but it might increase flickering when rendering animations. 
Stochastic – The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lighting calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal.

Self-illumination – The self-illumination color of the material.

Self-illumination Mult. – A multiplier for the self-illumination of the material.

Self-illumination Affects GI – When enabled, the self-illumination color affects GI computations.

Amount – A multiplier for the bump map effect.

Bump Type – Determines how the Bump Map parameter is interpreted.

Bump Map – Selects a texture for the bump or normal map. Leaving this unconnected turns off bump/normal mapping.

BRDF– Determines the type of BRDF (the shape of the highlight and glossy reflections). This parameter has an effect only if the Reflection Color is different from black and Reflection Glossiness is different from 1.0.

Phong – Phong highlight/reflections
Blinn – Blinn highlight/reflections
Ward – Ward highlight/reflections
GGX – GGX Microfacet highlight/reflections

GGX Tail Falloff – Controls the transition from highlighted areas to non-highlighted areas when the BRDF Type is set to GGX.

Color – The reflection color dims the diffuse surface color.

Glossiness – Controls the sharpness of reflections. A value of 1.0 means perfect mirror-like reflection; lower values produce blurry or glossy reflections. Use the Subdivs parameter below to control the quality of glossy reflections

Lock Highlight Glossiness to Reflection Glossiness – When disabled, you can enter different values for the Hilight Glossiness and Reflection Glossiness. However this does not produce physically correct results.

Highlight Glossiness – Determines the shape of the highlight on the material. Normally this parameter is locked to the Reflection Glossiness value in order to produce physically accurate results.

Use Fresnel – When enabled, makes the reflection strength dependent on the viewing angle of the surface. Some materials in nature (glass, etc.) reflect light in this manner. Note that the Fresnel effect depends on the index of refraction (IOR) as well.

Glossy Fresnel – When enabled, uses glossy fresnel to interpolate glossy reflections and refractions. It takes the Fresnel equation into account for each "microfacet" of the glossy reflections, rather than just the angle between the viewing ray and the surface normal. The most apparent effect is less brightening of the grazing edges as the glossiness is decreased. With the regular Fresnel, objects with low glossiness may appear to be unnaturally bright and "glowing" at the edges. The Glossy Fresnel calculations make this effect more natural.

Lock Fresnel IOR to Refraction IOR – Unlocks the Fresnel IOR parameter for finer control over the reflections. When this is enabled, the Fresnel IOR is locked to the Refraction IOR.

Fresnel IOR – The IOR to use when calculating Fresnel reflections. Normally this is locked to the Refraction IOR parameter, but you can unlock it for finer control.

Subdivs – Controls the quality of glossy reflections. Lower values render faster, but the result is more noisy. Higher values take longer, but produce smoother results.

Anisotropy – Determines the shape of the highlight. A value of 0.0 means isotropic highlights. Negative and positive values simulate "brushed" surfaces.

Rotation – Determines the orientation of the anisotropic effect in a float value between 0 and 1 (where 0 is 0 degrees and 1 is 360 degrees).

UV Vectors Derivation – Specifies the method for deriving anisotropy axes:

Local Axis – Uses a local axis for the anisotropy effect.
UVW Generator – Assigns a UVW Generator for the anisotropy effect.

Axis – Specifies a local object axis for the anisotropy effect when UV Vectors Derivation is set to Local Axis.

Trace Reflections – Enables reflections for the material.

Exit Color – If a ray has reached its maximum reflection depth, this color is returned without tracing the ray further.

Max Depth – The number of times a ray can be reflected. Scenes with lots of reflective and refractive surfaces may require higher values to look correct.

Enable Dim Distance – Enables the Dim Distance parameter which allows you to stop tracing reflection rays after a certain distance.

Dim Distance – Specifies a distance after which the reflection rays are not traced.

Dim Fall-off – A fall off radius for the dim distance.

Soften – Softens the edge of the BRDF at light/shadow transitions

Affect Channels – Specifies which channels are going to be affected by the reflectivity of the material.

Color Only – The reflectivity affects only the RGB channel of the final render.
Color+alpha – Causes the material to transmit the alpha of the reflected objects, instead of displaying an opaque alpha.
All channels – All channels and render elements are affected by the reflectivity of the material.

Color – Refraction color. Note that the actual refraction color depends on the Reflection Color as well.

Glossiness – Controls the sharpness of refractions. A value of 1.0 means perfect glass-like refraction; lower values produce blurry or glossy refractions. Use the Refraction Subdivs parameter below to control the quality of glossy refractions.

Index of Refraction – Index of refraction for the material, which describes the way light bends when crossing the material surface. A value of 1.0 means the light does not change direction.

Subdivs – Controls the quality of glossy refractions. Lower values render faster, but the result is more noisy. Higher values take longer, but produce smoother results.

Fog Color – The attenuation of light as it passes through the material. This option helps simulate the fact that thick objects look less transparent than thin objects. Note that the effect of the fog color depends on the absolute size of the objects and is therefore scene-dependent. 

Fog Multiplier – The strength of the fog effect. Smaller values reduce the effect of the fog, making the material more transparent. Larger values increase the fog effect, making the material more opaque.

Fog Bias – Changes the way the fog color is applied. Negative values make the thin parts of the objects more transparent and the thicker parts more opaque and vice-versa (positive numbers make thinner parts more opaque and thicker parts more transparent).

Fog Units Scaling – Enables unit scale multiplication when calculating absorption.

Dispersion – Enables the calculation of true light wavelength dispersion.

Abberation – Increases or decreases the dispersion effect. Lowering it widens the dispersion and vice versa.

Affect Shadows – Causes the material to cast transparent shadows to create a simple caustic effect dependent on the Refraction Color and the Fog Color. For accurate caustic calculations, disable this parameter and instead enable Caustics in the V-Ray Renderer. Simultaneous usage of both Caustics and Affects Shadows can be used for artistic purposes but does not produce a physically correct result.

Trace Refractions – Enables refractions for the current material.

Use Exit Color – Enables the use of Exit Color.

Exit Color – If a ray has reached it's maximum depth this color is returned instead of tracing the ray further

Max Depth – The number of times a ray can be refracted. Scenes with lots of refractive and reflective surfaces may require higher values to look correct.

Affect Channels – Specifies which channels are going to be affected by the transparency of the material

Color Only – The transparency affects only the RGB channel of the final render.
Color+alpha – This causes the material to transmit the alpha of the refracted objects, instead of displaying an opaque alpha. 
All channels – All channels and render elements are affected by the transparency of the material.

Type – Selects the algorithm for calculating translucency (also called sub-surface scattering). Note that refraction must be enabled for this effect to be visible. Currently only single-bounce scattering is supported.

None – No translucency is calculated for the material.
Hard (wax) model – This model is specifically suited for hard materials like marble.
Soft (water) model – This model is mostly for compatibility with older V-Ray versions (1.09.x).
Hybrid model – This is the most realistic SSS model and is suitable for simulating skin, milk, fruit juice and other translucent materials.

Color – Normally the color of the sub-surface scattering effect depends on the Fog Color; this parameter allows you to additionally tint the SSS effect.

Fwd / Back coeff – Controls the direction of scattering for a ray. A value of 1.0 means a ray can only go forward (away from the surface, inside the object); 0.5 means that a ray has an equal chance of going forward or backward; 0.0 means a ray is scattered backward (towards the surface, to the outside of the object).

Light Multiplier – Specifies a multiplier that controls the strength of the translucent effect.

Scatter Coeff – The amount of scattering inside the object. A value of 1.0 means rays are scattered in all directions; 0.0 means a ray cannot change its direction inside the sub-surface volume.

Maximum Thickness – Limits the rays that are traced below the surface. This is useful if you do not want or don't need to trace the whole sub-surface volume.

Cutoff – A threshold below which reflections/refractions are not traced. V-Ray tries to estimate the contribution of reflections/refractions to the image, and if it is below this threshold, these effects are not computed. Do not set this to 0.0 as it may cause excessively long render times in some cases.

Double-sided – When enabled, V-Ray flips the normals for back-facing surfaces with this material assigned. Otherwise, the lighting on the "outer" side of the material is computed always. Can be used to achieve a fake translucent effect for thin objects like paper.

Reflect On Back Side – When disabled, V-Ray calculates reflections for the front side of objects only. Checking it makes V-Ray calculate the reflections for the back sides of objects too.

Use Irradiance map – When enabled, the irradiance map is used to approximate diffuse indirect illumination for the material. If disabled, Brute Force GI is used in which case the quality of the Brute Force GI is determined by the Subdivs parameter of the Irradiance Map. This can be used for objects in the scene which have small details that are not approximated very well by the irradiance map.

Fix Dark Edges – When enabled, fixes the dark edges that sometimes appear on objects with glossy materials.

Energy Preservation – Determines how the diffuse, reflection, and refraction color affect each other. V-Ray tries to keep the total amount of light reflected off a surface to less than or equal to the light falling on the surface (as in the real life). For this purpose, the following rule is applied: the reflection level dims the diffuse and refraction levels (a pure white reflection remove any diffuse and refraction effects), and the refraction level dims the diffuse level (a pure white refraction color remove any diffuse effects). This parameter determines whether the dimming happens separately for the RGB components or is based on the intensity:

Monochrome – Causes dimming to be performed based on the intensity of the diffuse/reflection/refraction levels. 
Color – Causes dimming to be performed separately on the RGB components. For example, a pure white diffuse color and pure red reflection color yield a surface with a cyan diffuse color (because the red component is already taken by the reflection).

Glossy Rays As GI – Specifies on what occasions glossy rays are treated as GI rays:

Never – Glossy rays are never treated as GI rays.
GI Rays – (Default) Glossy rays are treated as GI rays only when GI is being evaluated. This can speed up rendering of scenes with glossy reflections.
Always – Glossy rays are always treated as GI rays. A side effect is that the Secondary GI engine is used for glossy rays.

Refl. Gloss. Interpretation – Controls how Reflection Glossiness is interpreted:

Use Glossiness – The Glossiness value is used as is, and a high Glossiness value (such as 1.0) results in sharp reflection highlights.
Use Roughness – The Reflection Glossiness  inverse value is used. For example, if Reflection Glossiness is set to 1.0 and Use Roughness is selected, this results in diffuse shading. Conversely, if Glossiness is set to 0.0 and Use Roughness is selected, this results in sharp reflection highlights. Note that the Roughness parameter itself has no bearing on the results of this option.

Use Environment Override – Enables the use of the Environment Override color.

Environment Override – A color or texture that is used as an environment for the material.

Environment Priority – Specifies the environment override priority when several materials override it along a ray path.