ZBrushCentral

Lightcap shadow and strength [Answered]

ZBrush Usage Questions
#1

Can someone please explain to me how shadow is connected with the light.

I have an example head lit from two lights in my simple example and lets say I want the right light to cast shadow and the left only to fill in (so I turn off the shadow on it) when I do this it is not affecting the shadow from the right light, meaning that it is not brightening it up at all, only if I turn the shadow on the left light it starts to work but then it casts shadows where I don’t wont them.

Is this supposed to work this way?

#2

To get the effect you are after you need to use the LightCap controls in the Light>LightCap sub-palette, not the Lights at the top of the palette:

  1. Turn off the Lights at the top of the Light palette by clicking on them, otherwise they will affect the scene. (You may want to adjust the Ambient slider later).
  2. Select a good base material such as the SkinShade4.
  3. Open the Light>Lightcap sub-palette and press New Light. Drag in the image thumbnail to position the light.
  4. Repeat for the second light, this time setting the Shadow slider to 0.

With a BPR render this should give you the result you want. Adjust the various options in the LightCap sub-palette to fine tune.

I’ve attached the LightCap shown in the images. Load it using the Light>LightCap>Open button. Note that the currently selected material will affect the result.

Attachments

LightCap01.jpg

LightCap02.jpg

#3

I have all the old type lights and ambient off, I am using only the LightCap lights. So to visualize what I mean, I made a test scene with just two lights left and right both have exactly the same settings like on the attached image. When left light has the shadow set to 0 it barely lightens up the shadow, I mean that you still can see the light contributing to diffuse color but it is not affecting the shadows, they are a little bit brighter just because the surface below them, Diffuse color is brighter. I was expecting this to work more like it does in other 3d packages i.e. 3dsmax. It looks like the shadows are overlaid on top of whatever is underneath at the end so (kind of like a layer in Photoshop) so this is why no matter how much I increase strength on the left light (with the shadows off) it will never be able to remove shadows of the right one. I found out that it kind of works like there is a 100% pool for all lights for shadows and balancing with this I can achieve results I need (I have attached several images showing this on different shadow percent levels)

So I have been tweaking this for a while and I came up with the solution that works it is just something different than I expected. I am tweaking all at the same time light strength, shadow and also I separate my specular from diffuse lights (this helps a lot) and this allows me to get what I am after. It is a bit more laborious than in 3ds max but I can live with that.

01.jpg
Settings

02.jpg
Left light shadow: 0

03.jpg
Left light shadow: 25

04.jpg
Left light shadow: 50

05.jpg
Left light shadow: 75

06.jpg
Left light shadow: 100, so as I said when both lights are exactly the same and have both 100 shadow they equally contribute to shadows, kind of like they both are now at 50% each

#4

Many thanks for posting your test results - very useful - and I’m glad you found a solution.