Welcome , we will continue our series on getting started with VRayforC4D . In this session we will talk more about some of the other material types that VRay offers and then we will get started with the Physical Camera , its been some time since our last tutorial and VRayforC4D has advanced so we will also include some of the new things that you might have seen in other tutorials outside of the Basix series , lets get started !
Advanced Material Changes
To start off keep in mind that some the “theories” that we talked about in the last tutorial regarding materials still remain valid , we are only going to talk about the most recent changes and how these changes will effect our new workflow .
The advanced material specular layer has now been changed to a new UI and adds a few things to help users to create more realistic materials , and the new core ( v2.55) brings a number of new features including interpolation for the specular layer and a flakes layer, the flakes layer is also part of the new VRay Car Paint material which we will cover in more detail later on in a future part .
Flakes Layer ?
In real life , metal flakes are a tiny bits of of type of a reflective metal , these flakes are often added to paints and blended in to create that shiny effect on paint jobs , as these are mostly random and reflective on their own , at the same time its often difficult to add them our materials ( in 3d ) without them looking fake . Thankfully now there is a new feature to simulate the flakes , and in order for VRay to do that , currently its going to generate a bitmap based on a mixture of textures that represent the flakes , and as mentioned , flakes are also a part of the Car Paint material so there is going to be more that in a future tutorial .
Specular Layer Changes ( v1.8-1.9 )
The new workflow around this layer is now much simpler , fresnel is on by default and there is no longer ( when fresnal is used ) a large transparency box to get on the way of making changes .
The fresnel options as they are important have been moved up and now you can link both highlight and reflection glossiness with a checkbox which is very helpful , you can uncheck this box for a custom value for either of them . you will also notice new interpolation options for each specular layer .
interpolation was originally meant to be a fast way to render glossy reflections , however it can cause a lot blotches to appear on your surface and it flickers a lot when used with animations , so i wouldn’t recommend using interpolation in most cases and only use for experimental stills , simply rely on the use LC for glossy rays as its the best way so far to render blurry surfaces fast with VRay .
This is as far as it goes for changes at the moment , now we can look at the other material types and what they do.
VRay Blend Material
This material can be used to combine two or more materials based on an opacity map , the map is defined by by the coat material which is on top of a base material , to use this material simply add a base material to the base link and add the other materials which have a texture or a shader in the material weight channel ( or alpha channel )
VRay Displacement Material
Displacement is one the many strengths of Vray and once you master it or even learn the basic use of it , it can save you hours of modeling , this material is what we use to add displacement to our objects , seeing it as a separate material might be confusing at first if you are coming from the Cinema 4D material background but its rather simple and straightforward , here is here is how you can add the displacement materiel AND the normal VRayAdv Material onto a single object :
Simply add your displacement materiel first on to the object and once you are done mapping it , add the actual VrayAdvMat on top of the object and make sure to enable the “Mix Texture” option on the second tag
The materiel has a number of different options , but as this is only a basic tutorial , we will only focus on the 3 important parameters
- Amount : This determines the ” Strength” of the displacement .
- Edge Length : This is the *Quality of the displacement : V-ray refines displacement based on the distance of the sub-triangles generated during the render time to improve the displacement without generating additional actual geometry , shorter distances between these “sub-triangles” means *higher quality but more resource consumption ( more RAM used ) , and longer distances mean *lower quality renders and less resources consumption .
- View Dependent : this tells vray to use pixels as a base to calculate the distance between sub-triangles instead of world units , in most cases , you will use this for close up shots ( the displaced surface is close to the camera ) .
Lets look at some example of this to make more sense of what’s actually going on , the example scene is a displacement texture of a tire ,
this first render is made with default values , notice the bad edges around the corners
Thats happening because there isn’t enough subtriangles at the moment , so to fix this , we could use some more subtriangles , and since this object is close to the camera , am going also use the view dependent option , here is the same render with a lower edge length value with that option on :
even tho the very close up on this one resulted in a very sharp displacement , it can actually use more sub-triangles when zoomed out , this is the final render of the tire with a edge length of 0.5 but *much more RAM was used , so keep an eye on that task manger ( RAM ) when changing this parameter if you can .
The VRay Physical Camera
VRay’s Physical camera is one of the essential use all the time tools , it provides you with exposure controls , accurate motion blur and DOF adjustments and much more , lets look at some of the parameters for the tag and then lets see how the usual workflow is like with it :
- Zoom Factor : this is pretty obvious , and also needed when matching certain SLR lens’s .
- Lens Distortion : this defines the amount of distortion when there isn’t a lens profiles being used
- Vertical shift and horizontal shift : these two “offset” the FOV Vertically Or horizontally during the render time , rarely used since the Cinema 4D camera has a very good options for both which VRay supports , in these two pictures , the camera position have not changed and only the Vertical shift value was changed ( notcice the almost straight line in the second one )
- Vignetting effects : adds vignetting to your render , very much recommend setting this value to 0 and adding Vignetting in post if you desire .
- White Balance : similar to the what would you normally find in a digital camera , the physical vray camera has also a white balance option , however its defind be a custom color here , and it also has a few presets . the most common way of using this is when using a physical sky with the Daylight preset .
Exposure and Depth of field with the physical camera
At this point i should really point out that knowing the basics of working with a real camera can help dramatically when working with all of the options of the physical camera , so make sure to look for guides or tutorials online for that , its even better if you would grab a camera and learn how it works , once you got the basics , it all translates in our 3d app or renderer .
Adding stops or removing them can be really a good to control your render , & vray actually makes it easier for you by providing a “fixed increments” option which will use actual numbers used by a real camera for the f number , shutter speed , and ISO , so best to use that whenever using a physical camera .
And just as in a real camera , the F number and shutter speed will affect the DOF and motion blur accrued , here is a basic way of working depth of field with the physical camera :
The “focus point” is defined by the end of the camera cone , and in the latest c4d releases you have a picker that can tweak the cone ( or the focus distance ) by clicking on a target in the view port
At this point all you have to do is to turn of the Depth of field setting and set a proper f number ( f-stop ) , and if you dont want to to effect the exposure of your render while still being able to tweak the f number , simply enable “Store Exposure” and this will tweak the the shutter speed for a consistent exposure
Additionally you can also add some bokeh to for that nice bokeh effect to your shallow depth of field render
This completes this part of the series , if you have any questions about the tutorial or any other vray related , leave your comment below and will try to answer them .
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