If this meter is full then you have too many parts.
Each creation created has a limited amount of "complexity" that can be added to it. This is because the game does not load a single model, instead loading multiple variables that form the creation, therefore limiting the amount of creation variables (type of limb, part size and deformation, location etc.) the computer has to load optimizes performance when using the creatures, otherwise creations would take too long to load on slower computers.
Adding parts (such as mouths on a creature) will increase the complexity of the creation until it reaches the maximum amount, at which point nothing else can be added to the creation. Parts will be coloured red when they cannot be added due to exceeding the complexity limit, similar to if they are too expensive to add.
Creations that exceed the complexity meter will not be pollinated, cannot appear in game and are marked with a red complexity symbol on their Sporepedia card.
The maximum amount of complexity on any creation is approximately 75 points.
To remove the complexity limits, refer to the Cheats article.
For a creature body with 2 spine segments (the smallest size allowable; each with a complexity of 0.5) and nothing else has a complexity of 1, allowing for 74 complexity points worth of additional features on the creature.
In normal game play, creatures will always require a mouth part in order to be saved and uploaded, and by extension played as. This is because a creature requires a mouth in order to eat, and at least one social and combat ability to interact with.
Here are the costs in terms of complexity points that each of the items in the Spore Creature Creator uses:
Each arm/leg segment has a complexity of 1.5. The default graspers/feet have a complexity of 0, excluding the Robot parts which have a default complexity of 1.
You can use the Asymmetry tool (Hold the 'A' key while moving a part) to move the singular details of a certain part, this can allow you to create features on the back (such as spines or plates) for half of the complexity and DNA cost.
You can use Limb segments as a suitable, lower complexity replacement for a longer tail feature on your creature, and can be used to create splits in the tail for more intricate designs or multiple tails.
If you are playing through the Story mode, is useful to attempt to optimise your creation's complexity as much as possible, as this will give you more complexity to add more clothing in later stages.
Some parts provide the same or better abilities but with lower or equal complexity ratings, take this into consideration if a specific theme is not a priority.
If you have completed the Creature Stage, it is a viable option to downgrade the parts of your creature, or take them off completely, this can notably reduce your creature's complexity, and the abilities of your creature are not as important in other stages. These abilities can also be completely replaced by better abilities in Galactic Adventures.
Most Detail Parts have a complexity rating of 1, you can use this to count how much complexity your creation has left before it is full.
Clothing and Captain Outfits
In outfit editors accessible from the Tribal Stage onwards, players can add clothing parts to a pre-existing creature, clothing part complexities are added on top of the complexity of the creature being outfitted.
Buildings
Buildings (in the Civilization and Space stage) require a minimum of 3 parts in order to be saved or uploaded.
Vehicles and Spacecraft
Similar to Buildings, vehicles and spacecraft also require 3 parts added on the creation in order to be uploaded.
