The concept art and audio design zone takes 10 days, which is perfect for our cycle time of 10 days per zone. However the other stages have different times. Scripting and tuning take less than 10 days per stage. The script writer might have to help two teams. The designer who does the tuning pass can help out with some of the level design tasks or even testing.

For the stages that require more than 10 days per zone, we need to start adding people in parallel. For example, we would add a second level designer. The two levels could then effectively finish one zone every ten days.

Since the hi-res artists require 30 days per zone we might have to have three total hi-res artists to balance our flow. There are three different ways to add people to help out:

1. Have multiple hi-res artists work on the same zone simultaneously.
2. Break up the hi-res stage into a more detailed specialized flow (e.g. texture artist, prop artists, static geometry artist).
3. Have multiple hi-res artists working on multiple zones in parallel.

Any of these solutions will work under different circumstances. Solution number one wasn't best because our level editing tools did not support simultaneous editing on the same zone. Solution number two wasn't best because the specialized flow wasn't balanced.

We already had most of our textures and props finished. We chose solution number three. Each hi-res artist still required 30 days per zone, but the work was staggered to allow hi-res zone work to be finished every 10 days.

Our Heijunka board then looked like this:

Each person has one zone of capacity. By adding level designers and hi-res artists, we can add more cards per stage because we have added more capacity.

We have now established a clock rate that is the same for every stage of level production. This clock rate (10 days in our example) is called the "takt time". By maintaing and even improving our takt time across the entire stream we can level production and effect real improvements as we address waste.

Reducing Waste

We might be happy stopping here. We have a balanced and predictable production pipeline in place. Many developers would enjoy getting here. However the tools of lean production allow us to take things a lot further!

The first principle of Lean is to reduce waste. We have addressed many of the wastes identified by lean in setting up our Heijunka board, but I want to highlight some of the others that particularly to game production.

Many of these wastes can be identified and corrected by the team itself. This is the ideal way to eliminate waste. The main tool for this is the time-box. The time-box will exert subtle pressure on the team to find ways to become more effective. In our example above, we identified a cycle time of 10 days and balanced the entire stream to achieve this.

What happens when the product owner challenges the team to reduce their cycle time to 9 days? Will we lose 10% of the value of the assets? Surprisingly we don't! The first reaction to tighter cycle times if for the team to remove inefficiencies in how they work.

Let's use a real world example. One project in production had 10 day cycle times for the zones in their level. When they wanted to reduce that cycle time by 20% they exposed some bottlenecks.

The biggest bottleneck was the concept art stage. They only had one concept artist available and that artist was sitting across the building with the other concept artists. The concept artist took 10 days to create a dozen drawings for each zone. There was no way to get these drawings any faster.

In team discussions it turned out that the level designers and hi-res artists didn't really need all these drawings. Because the concept artist was separate from the team, much of the concept art was based on wrong assumptions. The concept artist didn't like hearing that much of his work was ignored.

The solution was to move the concept artist next to the level designer and hi-res artists. This allowed them to discuss the layout and quality bar of the work being done. As a result, there were far fewer drawings that needed to be created and the quality of the final product actually improved.

This is an example of the waste of handoffs (one of the seven wastes defined by Lean). Documentation is a major source of handoff waste. Documentation has its place for recording knowledge, but it's not a replacement for face-to-face conversation. By applying this practice to every handoff in the stream, the team was able to apply similar time savings across every stage. The team seating area ended up resembling the arrangement on the Heijunka board itself.

In the example above, the team went from producing a level every 16 weeks to producing a zone every week. With seven zones per level, the ultimate improvement to level production was 56%.