Glowing in blender cycles

Want to master Blender? Click here! and get our E-Book

By default when using Cycles or Eevee in Blender, there are no post-processing effects, including glow. This means that no matter how bright an object is it will not radiate that glow effect that we so often see in a regular photograph when a bright object is present. So how do we set it up?

In general, we use the compositor to make a glow effect in Blender. We do this by setting up a glare node set to fog glow and connect it between the render layer and composite output node.

In the rest of this article we expand our explanation on this basic setup and we’ll cover a few methods for creating glow as well as their options.

How to make a glow effect in Blender

To have a prominent glow effect in a scene we either need a bright light or an object hit by intense light.

Depending on the render engine we use, the way to produce glow differs. In Eevee we have a bloom effect in the post processing render settings.

In Cycles we need to use the compositor to create the glow effect. Since there are no post-processing effects in Cycles by default.

However there is a custom build maintained called K-CyclesX that has a few post-processing effects including a glow for Cycles. You can get it here:

The first thing we’ll need for a glow effect is a proper scene, this will need to include either a very bright light shining against an object or an emissive material.

For this example, we can use a sunlamp and set its intensity fairly high. For this example, I set it to 10, any light should work though as long as the intensity is high enough.

We can also setup an emissive material to create the glow by going to the material and increasing the emission color value as well as increasing the emission strength.

Note that I’ve just used a newly created material for the example below so that I can quickly adjust the Principled BSDF node values without having to go into the shader editor.

How to make a glow effect in Blender using the compositor

The first method we’ll go over for achieving a glow effect is the compositor, this method will work in either Eevee or Cycles, and allows us to control.

To setup a glow effect with the compositor:

• Go to the compositing workspace
• Enable compositing
• Press shift + A and in the search bar type glare and select the glare node
• Connect the render layer Image output to the glare node Image Input, and the Glare node Image output to the Composite Input

Let’s take a look at what options we have on the glare node to adjust and customize our glow effect.

We have the option to change the quality of the image that is sampled when creating the glare effect, by default it is set to medium but high will sample from a full resolution copy of the input, in this case, the render.

The quality will also indirectly affect the glow radius, lower quality will result in a higher glow radius.

Mix is the factor that the original image and the glow are blended by. -1 would be only the original image, and 1 would be only the glare. We can use this value to affect how intense the glow is.

Using the mix factor, we can sample only the glow effect by setting it to 1 and then use a mix node set to add to composite it over our render.

This will give us the same results as the glare node would by default but will also allow us to make any compositing changes we’d like to the glow effect.

For example we could connect a Hue Saturation Value node to the glare output and change the color of the glow, we could also blur, the glow to increase the radius of it past the limit. So this is an alternative setup that gives us more flexibility.

Next, Threshold will limit what parts of the image can glow, higher values will result in less glow.

Last, we have size. This will change the radius of the glow.

How to make a glow effect in Blender using Eevee

Another way we can create a glow effect in Blender is by using Eevee’s built in post processing effects. We can use the same bright light or bright object setup and then just enable bloom and it will create a glow effect around the object.

To do this go to the Render Properties and Enable Bloom.

We can also use the values provided to adjust how our glow looks.

Threshold will set the limit for how bright something has to be to glow. While Knee will change how smooth the edges of the glow are.

Radius changes the size of the glow effect, while Color changes the color. However, by default it uses the color of the material that is glowing but we can also manually change it using this setting.

Intensity will change how intense the glow is. Clamp is in turn used to set a limit on how bright the glow can be.

Make something glow using subsurface scattering

We can also create a glow effect using subsurface scattering in our materials principled BSDF shader node. By having a very bright backlight as well as increasing the subsurface factor. Here is an example.

Besides the subsurface value we also have Subsurface Radius and Subsurface Color. Subsurface Radius lets us change the radius per color. The three values represent, Red, Green and Blue, in that order, if we increase the Red value it will cause our subsurface glow to look more red as well as increasing its radius.

Subsurface color will also give us control of the color without changing the radius.

You may notice that by default in Eevee light doesn’t properly shine through objects. We can fix this by going to the material properties and enabling subsurface translucency for that material.

Make something glow using translucency

We can also achieve a similar effect using translucency, translucency behaves similar to subsurface scattering but not exactly the same. Applied to basic objects it will appear as the inverse of diffuse, being lit on the shaded side and dark on the lit side, if we apply it to a more complex object it looks something like this:

Compared to normal diffuse lighting:

To make something glow with translucency in Blender follow these steps:

• Add a material to an object, and go to the material workspace
• Add a add shader node and a translucent node
• Connect the add shader to the output of the principled bdsf
• Connect the translucent node to the bottom node of add shader

Note that for translucency we will need a brighter light or a lower limit on what can glow for the material to glow. In the example below I’ve increased the sun light’s intensity, you could also modify the color being used by the translucency by increasing it’s intensity, for a solid color this can just be done by changing its color value.

You can increase this value past one by selecting it and typing the value you want it to be.

Final thoughts

A glow effect can really help emphasize just how bright an object is, without it objects may not look as bright as they are. Glow can also help soften an image. In Blender we have multiple methods for achieving it and knowing how each one works can help us achieve the effects we want with much more ease.

Источник

Creating a glowing effect with nodes

I want to achieve that light glowing effect. What material and what nodes do I have to use?

3 Answers 3

There is a simple way to create a glow effect in Cycles.

In the material section, Choose «Transparent BSDF» or «Glass BSDF» as the surface and the colour of your choice.

Select «Emission» in the volume and choose the colour as white.The strength can be of your choice

Add a place below the cube

Add another cube and scale it up slightly by pressing S and dragging the pointer.

Make the colour of the cube black and choose the surface to be «Emission»

Go to modifiers, chose wireframe, edit the thickness to your liking.

1. Place the wireframe over the cube and then Render.It should look similar to the example below:

Assuming Cycles, you can do something like the following :

Create a cube and set up a material similar to that described in this answer to generate the variation of warm glow of the centre of the cube.

Activate Freestyle and adjust the line width for the thickness of the lines.

Use the compositor to add a ‘fog glow’.

For a more convincing result, rather than using Freestyle you could model the cage around the light using a separate mesh so that it has some actual geometry (rather than being simple, flat, automatically generated lines). An easy way to generate such a cage is similar to this answer to Duplicate the object ( Alt D ), go into Edit mode on the duplicate, select all with A , press X and select Only Faces. Come out of ‘Edit’ mode and add a Skin modifier. You can adjust the size of the skin by varying the Vertex Radius ( Alt — A ) while vertices are selected. Assign a suitable material to the ‘cage’.

Источник

Want to master Blender? Click here! and get our E-Book

We can’t use Bloom the same way we do in Eevee since Cycles does not have a bloom feature built into the render engine. Instead, we add the bloom effect in post-production. This is how we can do it.

After your render has finished, go to the compositing workspace and check «use nodes». Between the Render layer node and composite node, add a glare node from the filter submenu after pressing Shift+A. Set the type to «Fog Glow» and quality to «high» then adjust the threshold, mix and size values for your scene and desired result.

Now, of course there are multiple ways we can do this and this may not be the best, but it is definitely the fastest. Let’s explore Bloom with Cycles a bit more.

What is bloom?

According to Wikipedia Bloom is an effect that is caused by a camera’s inaccuracy to focus.

In normal conditions the camera can focus well enough but when excessive amounts of light is added, the bloom effect becomes much more visible.

The effect is most visible in areas of great contrast, such as from an overexposed window viewed from inside a dark room. In that case the bloom will spread from the window out into the darker room before it fades away.

Take this image for example. It looks almost as if you could touch the light.

Bloom is an attractive effect that is often desirable. Sometimes we can see it with our own eyes as well since our on-board camera isn’t perfect either.

We can also fake bloom in most image manipulation software or compositors. Blenders compositor is no exception.

Another cool feature we can use in the compositor is masking with cryptomatte. You can check out the article here:

Why isn’t bloom built into Cycles?

The reason we don’t have bloom in Cycles is because it is a ray traced engine. A ray traced engine just tries to mimic how light travels and it does so pretty well. So well in fact that if we want a scene to look photo real we sometimes have to add post-processing effects to mimic the faults of the camera.

Bloom among other light artifacts that we can get from a camera isn’t part of the ray traced calculation. We either get it with a real camera or we have to simulate the effect afterwards. Even if we had a checkbox to add bloom to Cycles, it would still be a post processing effect. To have a ray traced engine calculate bloom would be very computational intense and hard to implement.

In Eevee, everything is approximated and «cheated» by using different techniques to speed up the rendering. In such a render engine it is only natural to add post-processing effects straight into the render engine. It is just another effect.

A word of caution though, be careful with effects that tries to recreate imperfections. As a rule of thumb, never add an effect that photographers would try to get rid of, or at least make the effect barely visible in those cases.

How can we create a Bloom or glare effect with a Cycles render?

In Blender, the glare node in the compositor is really at the heart of creating bloom for Cycles. But keep in mind that this is a separate tool within Blender.

There is no stopping us from using another compositor, like Nuke or Natron. We can even bring our render into a 2D image editor and create bloom there.

If you plan on creating your bloom effect in another application, I suggest that you export the rendered result as a multilayer openEXR file to maintain as much information as possible when you export.

A JPEG or PNG file format will compress your image and there won’t be nearly as much information to work with left in the image.

With that out of the way, lets focus on the compositor. This is a little work in progress that we can use to take a look at the effect.

A bloom effect creates a very soft feel to an image and if your render has fireflies in them or is too grainy as a result from too few samples the result may not look very good. In that case you can use the intel denoiser together with it.

Here is also a closeup on the node setup.

Glare node settings

First we have the glare type. We have several to choose from, and we can combine multiple glare nodes if we want more than one of these effects.

The options we have are:

For a bloom effect fog glow will most likely work best. But sometimes we may want another more dramatic effect. Here for example is a combination of fog glow and ghost.

There are only three more settings that are common for all glare types. These are threshold mix and quality.

For the glare type specific settings, you can check out the Blender manual.

The threshold value will allow the effect to occur for pixels that are brighter than the given value. For instance with a value of 1, pixels that are brighter than white will glow.

You can see that the default value is 1 and it is the value we used in our examples. This may sound confusing, after all, how can something be brighter than white?

If a surface is hit with more light and therefore overshoots a white value, we get a higher value for that pixel even if the screen only can output white as a result. The underlying number producing that brightness is actually lighter.

This is a good thing because then we can let glow occur when there are excessive amounts of light. Exactly what we want.

If you are having trouble with lighting, I suggest that you check out the Physical Starlight And Atmosphere add-on for natural lighting. For studio lighting, I think Pro-Lighting: Studio can’t be beaten.

The mix value will mix the output between the original image and the glare node output. Allowing us to dial back the effect without needing more nodes. A value of 0 is a 50/50 mix. For full glow effect we use 1 and for the original image we use -1 as values.

The last setting, we will cover that is common for all glare types is the quality. What it does is that for low and medium settings the effect is applied to a lower resolution version of the original image to speed up rendering.

This however will change the effect. For instance, with fog glow the glow effect becomes more spread on a lower quality setting. This does not mean that the end result becomes more pixelated or anything like that.

Do I need emission if I want bloom?

The short answer is no. You don’t need emission to have a bloom or glow effect in Cycles. But it certainly helps to create a more distinct effect since it is at the most contrast edges the bloom effect is most visible.

In the example above the surfaces are just diffuse. The bloom effect is then created from the excessive amounts of light hitting the surface, making a non-emitting object seem to glow. In this case the light hits straight not, but we can have bounce light strong enough for a bloom effect as well.

Final thoughts

Bloom is a very desirable effect. It adds atmosphere to an image or animation and creates mood. I also add to the realism or rather, our perceived realism of a scene as well.

Источник