What you are looking at
The goal is 3 m wide and 2 m high inside the posts: 6 m². That figure is only true dead square on. From anywhere else the mouth is a slanted shape, and it is smaller than the rule book says.
The m² readings are exact solid angles. Each one is how much of the ball's view the opening fills, turned back into the square-on goal that would fill the same amount. With Normalise distance on, that comparison goal stands at the same range as the ball, so range cancels and only angle and release height are left. 100% means square on, from 3 m or from 13 m.
Turn it off and the comparison is the goal seen square on from the 7 m mark. Now range counts as well: straight out at mid-goal height the goal reads about 3.7 m² from 9 m and about 8.1 m² from 6 m.
The picture's scale is eased so a long shot stays readable. The numbers beside it are not eased.
Why the goal leans
Both posts are 2 m tall, but they are not the same distance from the ball. From the right-back spot, about 10 m out and 31° off centre, the near post reads 2.17 m and the far post 1.86 m. From a wing take-off it is 2.52 m against 1.66 m.
Mouth reads is the same idea sideways: how wide a square-on goal would have to be to look this wide from here. It falls roughly with the cosine of the angle off centre, to 2.55 m from right back and about 1 m from the wing.
The posts are square, and 8 cm deep
IHF posts and crossbar are 8 cm square and painted in two colours, with 28 cm bands at the corners and 20 cm bands everywhere else. The model draws them that way.
The 3 m is measured inside the posts, so square on they take nothing. From an angle, the near post's 8 cm of depth gets in the way of sightlines aimed at its inside edge. From right back that costs 1.4% of the mouth. From the wing spot it is about 9.5%. In the goal-line corner the posts take three quarters of what thin lines would leave.
Within about 1.5° of the goal line, measured from the far post, the mouth closes completely. A thin-post model would still show a sliver.
The release point
A handball leaves the hand anywhere from hip height to well above the crossbar. Below 2 m the crossbar's depth never matters, because every sightline reaches the top of the goal from underneath.
Above 2 m the sightlines come down onto the goal and the crossbar starts trimming the top edge. A jump shot released at 2.6 m on the 7 m line loses about 0.02 m². A dive shot released at 2.8 m from 2 m out loses about 0.14 m². Height also tilts the goal away top to bottom, so the same spot reads a little smaller at 2.6 m than at goal height.
The ball has width
A size 3 ball is 58 to 60 cm around, about 19 cm across. A size 2 is 54 to 56 cm. For the ball to go in, its centre has to pass at least one radius inside the posts, under the crossbar, above the floor and clear of every limb.
That strips a band off every edge. Square on from 7 m, the usable mouth drops from 6 m² to about 5.1 m². Gaps around the keeper narrower than the ball are drawn hatched: they look open, but nothing fits through. Counting the ball, a basic-ready keeper a step off the line covers about 34% of what a 7 m throw can use, against 15% with thin sightlines.
The goalkeeper
He is built from your three numbers. Height sets every segment from standard proportions of stature: thigh and shin each about a quarter of it, the torso a little more. Wingspan, fingertip to fingertip, sets arm length. Weight per metre of height sets girth through the torso, thighs and arms. In basic ready, a 1.80 m, 80 kg keeper shows about 0.62 m² of body straight on; a 2.02 m, 105 kg keeper about 0.77 m².
He stands on the line that halves the mouth the ball can see and faces the ball. Off the goal line moves him out along that line. Shade slides him sideways toward the near post. Coming out pays: from centre back, with thin sightlines, the same keeper covers about 12% of the mouth on his line and about 17% two metres out.
- Basic ready. Soft knees, elbows at shoulder height, forearms up, palms to the shooter. The default against back-court throws.
- Arms high. Hands higher and narrower, taking away the top corners against long-range and jump shots and leaving the low corners to the legs.
- Wide Y. Deeper knees, wider feet, arms spread in a Y. A big frame against the pivot and other close shots.
- Near-post seal. Near arm straight up, near foot under the hip, far arm reaching for the far top corner. Built for tight wing angles.
- Star jump. The X at the top of the jump, about 25 cm off the floor, used on breakaways and some 7 m throws.
- Low split. Near leg along the floor toward the post, far knee down, body tilted to the near side. A reaction save, frozen.
What it still does not model
- The goalkeeper moving. Every stance is a frozen frame, and he stays square to the ball. From most spots a still keeper covers well under half of what the ball can use, so most saves come from reading the throw and moving.
- Bounce shots, spin shots and lobs. Every sightline here is a straight line from the release point.
- Defenders' blocks, the net and the back frame.
- The shooter. Handedness, arm path, or whether the shot is on at all.