The alJitterColor shader is useful for applying random color variation to scenes containing many objects. In this short tutorial we will add some variation to the hue and gain of some lemons using a combination of the Utility and alJittercolor shaders.
- Start off by assigning an alSurface shader to the lemons.
- Create a Utility shader and change its Color Mode to Object. This mode uses the name of the shapes to compute the color (this is necessary because the Signal attribute of the alJitterColor shader requires a unique value per object). Change the Shade Mode to flat.
Utility shader set to ‘Object’ Color Mode
The Utility shader outputs values between 0 to 1. However, the alJitterColor input uses in values which are non float values. Therefore we will need to multiply the output value of the Utility shader to a larger number.
- Connect the Outcolor R of the Utility shader to the Input 1 attribute of a multiplyDivide node. You will also need to increase the Input 2 to a higher value. In this case we have used a value of 80.
Utility shader connected to Input 1 of multiplyDivide node
- Connect the Output of the multiplyDivide node to the Signal attribute of the alJitterColor shader.
- Connect the lemon texture map to the Input of an alJitterColor shader.
- Finally, connect the Out Color of the alJitterColor shader to the Diffuse Color of the alSurface shader.
Final shader network
Now that everything is connected correctly, we can have some fun adjusting the hue of our lemons. Before starting, reset the values of the alJitterColor shader.
- We can use the Min Gain to apply a minimum random gain to the lemons.
Min Gain: 1 (left). Min Gain: 0.25 (right).
Max Hue Offset
- We can also use the Max Hue Offset attribute to randomly adjust the hue of the lemon texture. In this case we only want to make a subtle adjustment and so a small value of 0.05 was used.
‘Max Hue Offset’ of AlJitterColor used as a hue shift for the lemon texture
Max Hue Offset: 0 (left). Max Hue Offset 0.05 (right)
That concludes this tutorial on how to use the alJitterColor shader to randomly change the hue and gain of a color texture map.
The MtoA shader is available here.
A tutorial that covers using the curvature shader in Arnold to create a wear and tear effect can be found in the links below.
URs 3D has published a nice series of video tutorials using Arnold with Maya 2017. Some of them include using the ALSHADERS in MtoA.
Very excited to see Arnold for Maya as the default renderer for Maya 2017.
More information about some of the considerations required when using Maya’s native Color Management and Auto TX can be found here. The release notes are also available here.
More information is available on Autodesk’s official FAQ document.
Below is a video that briefly demonstrates Arnold in Maya 2017 that I contributed to.
Very excited to see Arnold for 3ds Max (MAXtoA) announced at Siggraph 2016.
It is available for download here. The user guide can be found here.
Some more information about the release can be found on the 3ds Max Blog on the area website.
Below is a video that I contributed to that shows some of Arnold’s functionality in 3ds Max.
I discovered recently (purely by accident), that you can get some pretty convincing refractive caustics using just the Sky shader.
Previously, I was under the impression that they could only be achieved using an emissive shader. However, using a HDR map with some high dynamic areas like a window or sun can give you some impressive results.
Tutorials here: MtoA, C4DtoA.
Autodesk Japan have made available the models used in the movie below from WOW inc.
‘Max Man’ and ‘Maya Man’ are made available free of charge for use within the software applications. The models are available here.
Below are Arnold renders of each model.
Gametextures.com have some impressive high resolution texture maps, including color, specular, normal, gloss and displacement among others. Below is a render of ‘Muddy Dirt Road’ with displacement and 6 subdivision iterations in Arnold.
Inlifethrill have released an impressive, high quality video tutorial course on Mastering Arnold Renderer for CINEMA 4D.
Snaptank have made an excellent high resolution alien scan freely available on their site. A great making of the scanning process can be found here. Below is an image of the scan rendered with Arnold (more here).