SusanGaSonG

The Jack-o-lantern started out as a sculpt of a pumpkin in ZBrush. I wasn’t sure if I was going to make it into a jack-o-lantern or just leave it as a pumpkin but as I got close to completing the sculpt I got curious.

That’s the best way to learn things right? To get curious. Look at something and think, ‘I wonder…’. And that’s what happened. I first decided to try to carve out the eyes. It didn’t work out quite as I had hoped. I used the insert brush in subtract mode but I had the dynamesh settings too low and I lost all the detail I’d already sculpted in.

After I fixed the dynamesh resolution I tried again, only to figure out that I needed to use subtract mode to get the results I wanted. Yeah, I forgot. Still that was pretty easy once I remembered to hold down the right keys. And it worked. I got nice indents for the eyes. I did a mouth that way as well. But the pumpkin wasn’t hollow or it may have been but because of the way I added the or subtracted the eyes and mouth that’s not how it worked. If I had wanted a hole all the way through that would have been different but, because I was trying to put a hole only through the shell, it didn’t work out the way I wanted. Here’s how it looked just trying to hollow out those openings.

The teeth for the mouth were fairly easy. I just used and insert box brush and dynamesh to create those. Though I did have to do a little work with the transpose gizmo that makes me so crazy. I think I might, and I stress might, be getting a little better at it.

Still it wasn’t the way I wanted. So, to get it hollow I tried using the insert brush to subtract a fairly good size sphere from within the pumpkin. The trick here turned out to be making sure it was large enough to intersect with the openings of the eyes and mouth. It took a couple of tries and I ultimately did it twice to get the size cavity I wanted. This is how it looked after I did that.

At this point, I thought I wanted to have the top come off, like you usually do with a jack-o-lantern. So I figured out how to use the masking tool and how to split the top off. The problem that created was that I was going to have to close up the openings created by subtracting that sphere from the inside. I basically had a shell but with the top edges open so it could have been more like a mold. I did try to close things up on the top but every thing I did, I kept loosing my detail. It also wasn’t really working the way I wanted. Since it wasn’t working I decided it wasn’t worth it at that moment to try to figure out how to re-project the detail back onto the surface. So I gave up on having the top come off. I backed up and left it as it was. That did make it a little difficult to paint the inside.

When it came time for color, I chose to polypaint instead of texture. I used an alpha and a color spray brush for all the painting. I probably could have chosen a better material than I did but at least it wasn’t the red wax. It took a little work to find the right color for the inside and at times it seemed to fade so I had to be a bit heavy handed to get good coverage. That turned out true for the outside as well. Here is an in progress shot of the painting.

Once I got it painted I played around with the lights. I was really trying to add one to the inside of the pumpkin so it would look like it was lit from within. But that didn’t play out quite right. I tried a few different placement options and types of lights and such and it just didn’t do what I wanted. Remember, this is still in ZBrush. I didn’t take the jack-o-lantern into another program to light it or render it or even paint it. All done so far in ZBrush. Still, I got some decent lighting I could work with.

Then I started with the rendering part. This I saw a little bit of at the ZBrush Summit this year and it stuck enough that I was able to poke around enough to figure out how to get the render as a file, and more importantly, how to get different render passes. And this is where it starts to get a little more involved.

So render passes are basically different types of renders of the scene. There might be one that is a mask that can be used to create a mask for say a background or a foreground, there might be a lighting pass, or a shadow pass, or a color pass. Two that can be very helpful are a subsurface shading or scattering pass and an ambient occlusion pass. The think about the different passes is they help to emphasize different area of the image. As an example, the ambient occlusion pass helps to mark the shadows and areas that aren’t seen as much. The subsurface pass can help to add a bit of depth and translucency to a material, for something like skin.

What you do with all these different passes is you take them into an image processing program and you composite them together. Depending on the order you put them in you can get different results. It seems to be very common to use Photoshop for the
compositing process. Since that is what I have, that is what I used. This project was my first attempt at compositing and I learned a lot. I had to try a lot of things. And I discovered how big a difference just one pass can make. As an example here is a
composite of the image with 5 different passes. The one missing is the ambient occlusion, well and the subsurface one but my material didn’t have any of that so I didn’t get one.

It’s ok but a little dark at the top, you can’t really see the stem. Besides just the different passes I also duplicated one or two of the passes to help emphasize some feature. I put these different passes on different layers and then I set them do different modes, like multiply, subtract, and things like that. I didn’t find quite the blend options I wanted at the time but I think I know where to look now.

So with all the passes and a few duplicates things were looking good. But I wanted an ambient occlusion pass. From my reading it seems this is one of the really powerful passes you can use. It took a couple of tries to figure out how to get that out of ZBrush, but once I did and was able to add it to the stack in Photoshop it made a big difference. You can see here how it all looks more realistic and balanced.

I’m super pleased with the way this turned out. I could say especially with it being my first attempt at compositing, but I don’t think that is really a factor in my being please with the result. I did learn a lot of stuff doing this and I know I made some mistakes, like not labeling the layers with the type of pass that I was using. That’s ok. The next one I do, I will remember these things and it will be even better.

Happy Halloween.