Making Of 'Bird of Prey'
Before getting started on this project, I tried to surround myself with as much reference and inspiration as I could before taking the plunge on the Zbrush canvas. I have great admiration for master bird carvers such as Floyd Scholz and I have always wondered if such wood carving techniques could be transfered over to the digital sculpting world. Some of the new features in the Zbrush 3.0 have convinced me that this is as good a time as any to try.
So the first thing I wanted to do was to go to the Tool palette and select a zsphere and begin blocking out the form.
Once you establish the direction of the head, I usually check it in the Preview window to make sure the front of the head is facing out the z axis and right side up. If it isn't, reposition and press, Store.
Next I want to place the eyes, which will help establish a constant reference when I later sculpt around the eyes. Checking reference for eye spacing and size is encouraged. On this occassion, I loaded up a polysphere which is now part of the selection choices in the library of tools. Reselect the zsphere head tool, then go to Tool:Subtool and Append the polysphere. Select the polysphere subtool and scale and position to the proper size and location using the Transpose feature.
Once the polysphere eye is in place and selected, we can press Tool:Clone. Select the zsphere head subtool and Append the clone of the polysphere. Select the polysphere copy subtool and press Tool:Geometry: Del Lower to clear away lower subdivisions of the polysphere. This is essential to be able to mirror the polysphere copy on the x axis, which can be pressed under Tool:Deformation:Mirror x. You should now have a pair of eyes. This would be a good time to label your subtools if you like. I will refer to the main tool as 'birdhead', and the subtool eyes will be distinguished as simply 'left eye' and 'right eye'.
The next part is just shaping the bird's form and just kind of sketching out the qualities of a raptor. It wasn't long while I was blocking out the form, that I noticed the nape of the neck was showing more rectangular spacing in the geometry than square. Also the spacing toward the bottom of the bird's bust was by far wider than that of the head area. This will have an effect on my ability to try get consistent fine detail with the feathers even once the subdivisions are as high as I can go. The more equidistant the spacing through the body, the more consistent the detail sculpting will be across the bird.
I am definitely going to need to create new topology.
To prepare for the retopologization, I simply select the bird tool and ensure that only the birdhead subtool is active (and not the eyes).
- Select Tool:Zsphere and draw on canvas.
- Ensure Transform:Edit mode is on, and then press Tool:Rigging:Select and select the bird tool.
- Press Tool:Topology:Edit Topology and you are ready to begin creating new topology.
Because the topology in the beak area is significantly denser than the rest of the body and the physiology of the actual bird beak is different from the feathered part, it seemed like an ideal place to break the two apart by creating separate topology.
Note: Before building new topology, be sure x axis symmetry is on for both meshes (press ' x' to toggle). This definitely helps speed things up.
As you may have noticed, I overlapped some beak geometry onto the head. This was to make sure I had plenty of leftover geometry to secure into the head mesh when it's built. When you're finished, press Tool:Adaptive Skin:Make Adaptive Skin.
Select the bird tool with the subtool eyes and Append the new skin you just made and rename accordingly.
Next we'll create new topology for the head of the bird. When it came to the opening in the mesh up by the bird beak, I needed to delete the rigging selection to gain access for closing the gap.
To do this:
- UnpressTool:Topology:Edit Topology.
- PressTool:Topology:Edit Topology and you can now reach geometry that was previously occluded by the rigging mesh.
Closing this off gives me extra geometry to work with for making modifications between the beak and forehead if needed. By no means is the new topology the best solution for the form, but it is certainly better than before. Make an adaptive skin and Append it to bird tool.
I then deleted the zsphere bird head tool from the subtool list and focused on trying to bring together the remaining subtools together to become more raptor-like.
After spending much time trying to fine tune the qualities that make a bird, an eagle, I then start to make note of the feathering of these types of birds. The next section will go into time spent preparing the alphas and figuring out the layering process.
Creating the Feathers
When I started looking into the feather options, I didn't know if I would go with a stencil technique or use the sculpting brushes. This time I decided to go with the sculpting brushes for nothing else but the fact that the DragRect stroke enables me to put down feathers quickly at any angle and size like the directional brush.
The first alpha I tried, I noticed that there was an auto fade that caused a loss of definition at the tips of the feathers. I didn't mind the top of the feather fading but I needed the bottom tip to be as crisp as I could get it. I decided to increase the size of the alpha, made sure the feather was aligned to the top and the essential details were kept in the center.
After trying the first test alpha feather, I then made a few more feather alphas for added variety so as not to have any major discernible repetition. Pressing Alpha:Flip H on any given alpha can also buy you one more alpha variant to break things up even more.
Return to the bird tool in Zbrush, and subdivide to level 6 or 7. In this case, 7 was the highest used. Now clone the Birdhead subtool and Append it twice to the subtool list. I renamed one clone FeatherSet.01 and the other FeatherSet.02. We'll save the BirdHead subtool as a backup and move it down the list using the arrow keys which are located at the bottom of the subtool list.
As a little safety precaution for the FeatherSet subtools, we'll click Tool:Layer:New for both subtools. Now if anything should go astray, we can always slide the layer slider back to 0 and start over. A morph target is also a good alternative if it's not already being used.
- Alpha = the feather alpha.
- Z Intensity = 25, with Zadd.
Click and drag feathers in the direction they would flow on the actual bird. Space them so that there is minimal overlap or at least little to no noticeable overlap of the feather details.
Cycle through your feather alpha collection finding the best alpha with a curve in the feather that compliments the form of the bird.
Don't forget to horizontally flip your alphas if the bow of the feather needs to run the other way. You may find you can get away with applying these feathers with Transform:>x< on to activate x axis symmetry. However, when feathering the front, top, and back views, it will become apparent when to turn off the symmetry and go freestyle.
When you have given the FeatherSet.01 subtool a good first pass, select and turn on the visibilty of FeatherSet.02 while FeatherSet.01 remains visible. Adjust the Z intensity of the standard brush to 28 now and draw a new set of feathers through the FeatherSet.01 subtool until they appear to overlap (or underlap) the feathers of FeatherSet.01.
Due to the nature of the auto fade of the sculpting brush alphas, the displacement intensity of the outer edge is less than the center. This makes it possible to slide the top of the feathers under existing feathers.
Once the bottom feathers around the neck are placed in a fairly filled out fashion, we can begin painting a mask on the undisplaced geometry. Begin with either feather subtool while the unselected subtool is hidden. Work your way around until the bottom straight edge is masked. When masking is complete, press Tool:Masking:Inverse followed by pressing Tool:Masking:HidePT.
Left to right:Masking, Invert Mask, and HidePt.
Repeat for the remaining FeatherSet and adjust masking if necessary. You can toggle the visibilty of the two subtools to check if the masking was thorough enough.
Once both featherset subtools are completed, you can turn on the visibility of the beak and both eyes to inspect the piece as a whole. I would frequently have either the beak or one of the eyes selected in order to view the feathers in the same value.
Sorting the Feathers
Next we need to tidy up the feather overlapping by either pushing or pulling the feathers that are not properly 'settled' such as the example shown here.
Notice the crashing of the middle feather into the left most feather? To fix this we can first set a morph target in the selected subtool by pressing, Tool:Morph Target:StoreMT.
To lift the middle feather out of the other, we'll set:
- Alpha = Alpha00.
- Z Intensity = 15 with Zadd on.
As we build up strokes over the feather, you can see it gradually lift out from the bunch, leaving the feather's detail. If you look closely, I accidentally pulled too much of the underlying surface through the inactive subtool.
Switch to the Morph brush, adjust brush size and intensity to suit, and push back any over extended surface.
Give the model a once over and look for any more areas that need this kind of attention. We are almost to the end.
Fluffing the Feathers
Remember that extra subtool that was our backup, named BirdHead? Select it and make sure it is at the highest subdivision. Turn the visibilty of the clones off. Create a New 3D Layer if you haven't already done so and begin drawing on feathers like before except this time, they are not to touch each other. You don't need to cover the whole bird but check your reference. In this case, the back of the neck is a good area along with the side of the neck. Basically you just want to break up the silhouette and give a feel of some depth to the feathered area.
Now under Tool:Layer move the layer slider back to 0, go to E Smth and S Smth and slide both down to 1. Lastly, move the Thick slider down to 0. Press Make 3D.
You should now have a new subtool created based on the strokes just made from the BirdHead subtool resting on the very surface of the subtool from which they were made.
- Return to the BirdHead subtool and make it visible.
- Move the 3D Layer slider back to 1 so the feathers are visible once again.
- Reselect the LayerSkin subtool with the feathers and press Tool:Geometry:Divide once.
- Select Brush:Zproject.
- Select Alpha:Brush00.
- Set Stroke:Dots.
With Zadd on, we'll now brush over the layerskin feathers until they take on the detail of inactive subtool above it. You may find you get better results projecting, by rotating the model to where the area you wish to project is parallel to the screen. Also make sure X symmetry is off for this part. If you wish, you can sculpt in more detail to make these feathers unique.
After you are satisfied with the indiviual feathers, we'll paint a mask over one of the feathers. Invert the mask, and invoke Transpose mode by pressing ' w'. Create an action line on the feather by clicking near its top, and dragging to near its bottom. You can now use the Transpose rotate feature and lever the feather away from the body.
Don't forget the middle circle of the Transpose action line can be used to twist the feather on the axis of the action line. Clear the mask when done and select a new feather to begin the adjusting process. Feel free to turn the visibility of the Birdhead subtool on to get an idea of how much to rotate the feather from the rest of the body.
When you have all the feathers positioned, turn on all essential subtools for evaluation. If there are still sorting issues with the feathers, use the Elastic brush like mentioned above or even try the Move brush to correct aggressive clipping.
And finally... Looking back in hindsight, I would have liked to have tried consolidating the the subtools into fewer, by Zprojecting details from one entirely onto another. This may require retopology again but may be worth a try in the future.
I hope this tutorial was helpful and assists you in your getting desired results in your future projects.