ZBrushCentral

Help with shadow art. Creating a sculpture that has a specific silhouette for 3d printing

ZBrush Usage Questions
#1

Hi there, I am trying to workout if it is possible to use Zbrush to create a shadow art sculpture. I have attached a picture of a physical sculpture that I made out of wax. It casts the shadow of two faces on a wall when a light is shone on the sculpture at a specific angle.

I am wanting to take this concept to the next level by using the sun as the light source. This means that I need to be able to see what the silhouette of my sculpture will be at specific angles that correspond to different times and days of the year.

Does anyone know how to set the camera to a specific angle (i.e one that corresponds to the angle of the sun rays on a specific time and day of the year)?
I am also struggling to figure out which perspective settings to use so that when I 3d print the sculpture, the silhouette will remains exactly the same.

Any help would be greatly appreciated.
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#2

Hi @jamesnielcook!

There are no position of the sun/time of year presets for the camera if that’s what you’re asking. The Universal Camera feature contains many options for defining and storing camera positions, but the burden for researching and inputting the values to approximate the light source’s position relative to your object would be on you.

#3

Thank you very much, I think that answers my question about the camera angles. There are a few online tools that calculate the angle of the sun’s rays at specific times so if I can input the angles into the universal camera that would be perfect.

From what I understand, the universal camera has different focal length settings etc which change the way the silhouette of the sculpture appears on the screen. If I can see the silhouette then I know what the shadow will be and the smallest change can have a big impact on the shadow. Do you know which settings to use such that the silhouette doesn’t change when I 3D print the sculpture?

#4

I haven’t the slightest idea. I’m skeptical that it’s even possible to simulate the sun that accurately in Zbrush–that sounds really ambitious–and current atmospheric conditions will change the quality of the shadow regardless.

My approach to this would be to approximate it as well as possible, then make some small, quick, coarse test prints to see how its working. The silhouette should stay the same regardless of size.

#5

Thanks very much. I will give that a try.

#6

I’d consider using something like Keyshot with the Zbrush to Keyshot bridge for this… or perhaps even Daz Studio. You may not have absolute sun positioning controls, but with decent HDRI skydomes, the lighting and shadow previews would be vastly superior to Zbrush for this application.

I haven’t used Bryce in years, but it used to have great sun/sky settings/controls (you can set azimuth and altitude)… Daz Studio has a GoZ like connector to Bryce, so you could GoZ from Zbrush to DS, then send to Bryce.

#7

Amazing, thanks so much for the help. I’ll give that a try.

#8

I wrote:

Actually, in Daz Studio, you DO have sun and time of day controls… and Studio is free. From the docs:

Sun-Sky

The properties in this group are responsible for establishing the position of the sun (the direction of the sunlight), controlling what the visible sun looks like when it is in view and creating the color gradient that represents the atmospheric skydome, which is then used to light the scene, show the sky to the camera, and show the sky in reflections.

Direction

  • SS Sun Node - Provides the ability to choose a node in the scene to indicate the direction from which the sun is shining; the direction of light is calculated between the position of the chosen node and the center of the environment dome.

  • SS Latitude -

  • SS Day -

  • SS Time -

  • SS UTC Offset (hrs) -

Sun

  • SS Sun Disk Intensity - Controls the intensity of the visible sun disk.

  • SS Sun Disk Scale - Provides artistic control over the size of the visible sun disk. The value 1.0 is the “physically correct” size, but due to the fact that people tend to misjudge the proper size of the sun in photographs, the default is the slightly more visually pleasing 4.0

  • SS Sun Glow Intensity - Adjusts the intensity of the glow around the visible sun disk.

  • SS Physically Scaled Sun - Controls whether the intensity of the sun is physically scaled. When enabled, a SS Sun Disk Intensity of 1.0 causes the sun to be as bright as it is in the real world; but it can still be used to tweak the intensity (e.g., a value of 2.0 would make a sun twice as bright as the real sun). Likewise, SS Sun Glow Intensity and SS Sun Disk Scale can still be used to tweak the visual aspect of the sun but have no impact on the total energy, which is automatically adjusted to compensate.

So with GoZ, it should be simple to fairly accurately preview your sculptures.