Arion 1.5.1 Release Candidate

Arion 1.5.1 features tour

RandomControl is very proud to announce the immediate availability of Arion 1.5.1!

This version brings so many new features and improvements it's hard to make a choice to highlight the most remarkable ones.

We invite you to take a tour of these exciting features, but our journey is just starting. We are already working on the next version and some terrific surprises...

Faster speed, better noise

Arion 1.5.1 comes with many improvements. Among them is probably the most discreet yet the most visible one: noise convergence.

We have improved the noise convergence again. The grain is finer and denser, the sampling more uniform. Arion now renders cleaner in less time, and that benefits your work.

We have also improved dramatically the noise during the real-time navigation for an even better and smoother user experience.

Sub-Surface Scattering

One of the most awaited features for a GPU renderer is now available with Arion 1.5.1.

Our Sub-Surface Scattering is entirely physically-based, capable of the most complex light scattering beneath the object's surface to mimic virtually any material in the world.

Arion's Sub-Surface Scattering is fully integrated into our brand new BRDF model. It can do forward and backward scattering (or both at once), has control over the density of the matter in a physical way and is not limited in any way.

Single Sheet Sub-Surface Scattering (S5)

Single-Sheet Sub-Surface Scattering was a RandomControl exclusive feature when it was originally released in fryrender.

We're bringing this awesome feature to Arion now, enabling you to render beautiful and really efficient lamp shades, leaves and vegetation in general, occlusion screens... And much more.

Thanks to the new BRDF, S5 is now fully compatible with roughness and dielectric transmission as well, and that is yet another exclusive feature of our technology.

Participating media (fog)

Participating media is one of those features that you were not particularly missing before, but once you have it, you can't go back!

Fog can be used in many situations to improve the realism of your scene by adding dust in the air.

Our participating media system is very powerful and flexible as it is based on our standard SSS material. You create a material, you point Participating media to it by typing its name, you enable Participating Media and that's it. You can then freely tweak your material to change the way the fog reacts to light.

For example a high asymmetry will give you very 'focused' fog that will look like glowing almost (like the red lights bike render), while a negative asymmetry will randomize the light scattering and make your scene look backlit by the fog. It's all a lot of fun!

Mapped emitters

Emitters can now be color and opacity mapped, and thanks to good programing and the new CUDA4, it's not any slower than plain color emitters.

Fireplaces, TV-set screens, mapped candle flames etc. are no longer a problem for Arion!

All this is of course editable interractively within Arion.

Real world emitter units

Arion 1.5.1 now supports real world, calibrated emitter units.

Watts, Lumens, Candela, lux and luminance are supported, as well as efficacy when applicable.

A great effort has also been made to make the emitters importance sampling as efficient as possible, for even cleaner renders.

You can also bend that importance sampling by attributing an importance factor to an emitter in the object properties panel.

Coated reflections

Arion 1.5.1 improved BRDF model comes with a significant improvement in realism and workflow: The plastic coatings.

In a traditional material to add a reflection, you would have added a second layer and played with the weight of layer 1 and 2 to get it right. Thanks to the coatings, you can now do that withing a single layer!

Plastic coatings allow for a material to look 100% reflective at grazing angles, according to the fresnel function indice (nd), while a material with 2 layers would reflect only as much as the weight value is.

Plastic coatings can be color and roughness mapped. We highly recommend that you use them, as they're fully physically-correct and greatly increase the realism of your render.

Integratable rough dielectrics

Yes you've read it right. Arion 1.5.1 integrates rough dielectrids! What does this means in practice?

It means that your rough dielectrics (like frosted glass) objects will render really fast with any emitter size, with full total internal reflections and caustics, not less!

This feature is unique in the world of rendering and is a very nice mathematical achievement.

The picture on the right has been rendered in just 5 minutes with 2 GPU using a physically modeled spotlight with a very small emitter.

Improved physical sky

We have improved the physical sky color fidelity in this version.

The difference between a render that looks natural and one the looks CG sometimes is just about getting the colors right.

Spectrums conversion had never been so right before in Arion, we can now render deep blue sky that looks just like the one through your window.

With the New GPS positioning tool, it's so easy to render true-to-life images of any place around the world.

Draft engine

Do you like the quality of the render above?

We're glad because it was rendered in an unbiased 'draft' mode using Arion 1.5.1 in a bit over... 2 minutes. You can take a look at a comparison between the regular unbiased kernel and the draft one by clicking here.

This kernel is really useful to setup a scene and navigate really fast, which is why it was originally made. But we found out that it was capabe of delivering final production quality in many cases as well!

The draft mode also comes in particularly handy to render animations, be it previews or final quality.

State of the art BRDF

Welcome to a new era of computer rendered graphics.

The new RandomControl BRDF version 2.0 is a major achievement for us. It's mathematically pure and perfect, anihilating energy loss without any compensation or patching. It is just doing it RIGHT.

This is a feature that you will see nowhere else, because nobody has addressed that problem fully so far. All the known models have some degree of energy loss, half-working compensation or are not compatible with some features like anisotropy.

Our model provides a final answer to that issue and ensures that your renders always look like they should, providing vivid, true-to-life light simulation.

The image on the right *demonstrates* how seamlessly our model goes from roughness 99 to 100, without any jump and with really perfect and pure whites, without a dark border at grazing angles.

The second thumbnail is showing a set of balls ranging from roughness 0 to 100, enclosed in an emitting grid shelf. The left image is Ambient occlusion, the right one is the full render.

Appreciate that it looks like a plain color, just like it should. Purity of carefully crafted mathematics at work!

Dielectrics improvements

Arion 1.5.1 is now equipped with a powerful Media Traversal Stack (MTS) that allows for proper interface between various dielectrics and indices of refraction.

With the enhanced total number of bounces, it's now possible to render anything that involves many transparent objects seen through each other.


Steresocopy live inside Arion's viewport, in real-time (anaglyph only).

We also provide an active/passive stereoscopy rendering mode (dual-renders with inter-pupillary distance) using our command-line rendering power tool RenderWarrior.


The falloff effect (formerly known as 'Custom nd') was only supported in fryrender as of today.

It is now fully supported by Arion 1.5.1 to help you create amazing drapes, clothes and any fabric material in general. But it can also be used to bend reality and create surrealistic materials!


Arion 1.5.1 is a native CUDA 4.0 application. It comes with pre-installed CUDA runtime software, you don't need to install CUDA toolkit anymore. Install Arion, the latest NVIDIA drivers and you're ready to go!

CUDA 4 allowed us to increase the maximum number of objects a scene can have. We also reduced memory footprint, stability at high resolution and a nice boost in performance (up to 80% on some scenes).

It also allowed us to unify some parts of our core engine. Now opacity mapping comes for 'free' and has no impact on rendering speed.

Material override

Material override is a pretty awesome feature. It allows you to define a unique material that will be used to replace all the materials present in your scene, for example to make a clay render.

The material override feature is also respecting your emitter materials, so your replacement pass matches exactly your beauty pass in terms of lighting.

New compositing channels

New compositing channels were included in Arion 1.5.1, giving you even more control on your final render.

We have added the Roughness and Fresnel channels that allow you to tweak your reflections in post-production.

But that's not all! Now you can also define 'shadows catchers' objects per material to render matte-shadows channels. All these improvements are included in Arion 1.5.1.

Wireframe override

Render stunning, Arion-antialiased wireframe render of your objects, with full illumination and materials features. Combined with the material replacement, you can even render clay with wireframe overlay while keeping your scene lighting.

In a few clicks, you're ready to post your artwork and its 'breakdown' images on a community forum, include it in your portfolio... In full Arion quality.

Improved UI: Scene tree

Arion 1.5.1 comes with a vastly improved user interface featuring a brand new 'Scene tree' that gathers all the scene data in one single list panel.

All the item properties are displaying in a second panel, freeing much space for the actual render and navigation area, materials library...

Scenes repository

We've thought that you would like to try your brand new software with some pre-made scenes to taste the speed, the quality and give a try to material editing without creating a scene on your own.

The scenes repository is here for you! It provides scenes that were selected for their speed and adaptability to a wide range of GPU memory sizes and performance.

And much more...

  • Exclude from camera (hide)

  • Decal mode shows emitters by color instead of power

  • Dispersion ON/OFF switch

  • Emitters and 'others' (like physical sky) ON/OFF switch

  • Color maps ON/OFF switch

  • Bump maps ON/OFF switch

  • Explicit material ID: Make your custom MatID channel

  • Explicit object ID: Make your custom ObjID channel
  • Better fresnel

  • LUA scripting

  • Emitters and Sun are now working together

  • Caustics ON/OFF flag

  • Ability to rename objects, camera, materials

  • Aspect ratio is saved in the file

  • FOV is now horizontally docked

  • Smoother navigation noise (antialiased)

  • Editable emitters in realtime...

...and more to come soon!

Special thanks

We would like to thank all our customers for their amazing works using Arion.

We are also specially grateful to the people who have helped us during the testing and the production of this fine release of Arion:

Fran Davey, John Strieder, Johnny Butcher, Pawel Filip, Marco Podrini, Raphaël Aguirre, Roman Vrbovsky, Shaun Keenan, Stéphane Moya, Luis Morillo and Héctor Pérez.