Ball Lighting Exercise
To begin project 01, I shot a set of photographs that would help me both match my camera and light my scene for integration. The set includes:
(1) clean slate image, (1) slate image with shadow, (1) slate image with a grey sphere, (1) slate image with a grey sphere and shadow, (1) chrome sphere, (7) different steps of exposures for HDR imaging. Below are contact sheets of my photos taken.
Contact Sheet for Scene and HDR
Shutter Speed - 1/200
F Stop - 8.0
ISO - 100
Aperture - 35mm
HDR - 7 step exposure
Next, it was time to take the cube and sphere slates into Maya to match the camera's perspective. With both the cube and sphere in place, I started to position a key light so I could try to make the shadows. This part was a little difficult as there was always a slight difference in the line up, no matter how much I nudged the light.
Once my camera was set up and my light angle matched, I began to create my fill and HDR light. For the key light, I had used a spot light, the fill, a directional light, and the HDR an aiSkyDome (Ball). I have never used an aiSkyDome for a HDR before. I was learning how easy it was to have a very blown out looking light in your scene when dealing with an HDR. It took a little bit of fine tuning on the fill light and aiSkyDome to get something much more balanced.
Below you will find my settings for each light as well as a scene set up shot.
When lighting, I used the image of the grey sphere to both position my directional fill light and color match it. Below is my grey sphere when all lights were applied to the scene. To the right is the grey ball I shot with a camera.
I created another render layer to make bounce light from the concrete visible. I disabled the stairs from rendering and played with the color to get that yellowish tint on the bottom of the sphere (Below).
Looking at it, I feel that I should go back and tweak the brightness of the bounce light. It doesn't seem as bright as the photo I took.
For my animation, I decided to turn the ball into an RBD and have it fall down steps through the pole's shadow. Included with the RBD, I used airField to help manipulate the ball in passing through the shadow and into the composition. I plan on going back and speeding it up so it will be more realistic.
Below are my settings for the RBD I set up.
Finally, I began compositing all my renders together. Using Nuke, I was able to achieve my progress render. For both the ambient occlusion pass and the shadow pass, I used a color correct node to readjust the color hue and value of each shadow. I connected the input to the background slate and the mask to each, the shadow and occlusion shadow.This will give me more customization and control of my render layers.
Beginning my week 2, I decided to create a new ball for my scene. I created a volleyball complete with stitching to roll through my shot.
I found was that my shadow plate was not in all shadow. I needed to edit the shadow plate so that the remaining highlight would be covered. I know that I cannot clone stamp the area as the ball's shadow goes over the area effected, there would be a circle of different cement pattern. Instead I decided to approach this issue through Nuke. Abby Riegel helped me with this technique to select out the white points from the black points using a combination of Keyer and Grade nodes. I continued to try to work out the process on my own. The edges and alpha bleeding pose an issue; the remaining will be fixed in Photoshop.
The final shadow slate.
I went back into my scene and readjusted my light to Billy's comments about using a directional light. I replaced my key light, a spot light with a directional light, and deleted my fill light only using the HDR as fill.
The pinch of my HDR was not directly toward the middle of my camera and had to readjust the sphere's texture placement. As my aiSkyDome does not rotate in real time, I matched up a sphere bottom vertex and the sky domes pinch and use the sphere as a parent to rotate the texture. Deleting the Pref folder did not solve this issue.
Approaching the Environment Shadow, I followed a method proposed in class. The background image was projected onto the stairs from my rendering camera.
Then that image was projected in a new layer from a camera located where my directional light would be. This way the shadow would all fall in the correct spot for the ball to go through.
In Photoshop, I manually selected out the light areas and painted them black. I used a white to fill in where all the shadows.
I realized that the stair shadow would not be visible and started creating some strange shadows on the ball as it rolled through. I also figured the white would be harder for Nuke to recognize correctly so I made the white red. I also made the bar shadow longer and filled in the 'stair shadow' with black.
Assigning a surface shader with projection from the camera at the key-light, I attached the latest file and got something like this.
Readusting my render layers I decided to add in a specular highlight layer. I will not that looking back of the exercise, I would like to change my key-light layer to have the ball with no color. This what it will only catch the value in compositing rather than over saturating the color.
Below will be a flip through of my different renders for compositing.
The RBD sim on the ball had to be redone and slowed down just to fill 3 seconds. I still feel that the simulation could have been a bit more bouncy. The sim was created by David Grzesik
Notes from critique were as followed:
The contact shadow is too sharp and should not be included in the light. Needs to be softer and masked into the ball's shadow. - Kyle Cody
Break up the specular and make the surface rougher, it is too intense. Include a bump on the ball. Disrupt the material a little. - Billy Dongjoon Jang
The environment shadow needs a little work. The white is not in shadow. Consider using geometry to create the shadow. More accurate. - Kyle Cody
Taking the mentor's critique, my final render turned out as such.
I started by going back to my material. I added a procedural leather bump map to the original Volleyball Material that was very slight. This helped to disperse the highlight along the ball's surface. I also reworked the material's attributes to be a tad more rough.
I decided to also make the ball a little dirty. I created a new aiStandard for a dirt texture and used a LayeredTexture node to blend both the dirt texture and the Volleyball Material using a Cloud alpha. The cloud procedural will give me that small mount of soft edges you get on a ball with dirt smears. I added a normal map to create slight dimension to the dirt.
If you have any thoughts or would like to make a suggestion, I would love to hear from you. Leave a comment down below.