Copyright © 2015 Curt Hill Models and Textures Making your entity interesting.

Copyright © 2015 Curt Hill

Models and Textures

Making your entity interesting

Introduction• Single cubes are not impressive• Rather we wish to build up our

entity with a series a various sized cubes to go with the cubist theme

• We have to be able to:– Size them– Place them– Connect them– Texture them

• First the coordinate system


Coordinate System• You should all be familiar with

Cartesian coordinates– X is left right– Y is up down

• This is not enough for a 3D space• We need X, Y, Z

– This is the order we always specify them

• However, it is not the extension we would expect


3D Coordinates• In this coordinate system, the

Cartesian plane is turned 90° rotating on the Y axis:

• X comes out of the screen toward us– Positive is moving towards the viewer

• Y is up-down– Positive is down

• Z is left-right– Positive moves towards the right


Pixels• The units of position, size and

other things are always in pixels– Size must be an integer– Position may be fractional, so a float

• The Minecraft pixel is not the screen pixel

• A block is a cube 16 pixels on a side

• If we have a 32 by 32 texture each Minecraft pixel gets four texture pixels


Coordinate Zero

• In some sense the X and Z zero points are relative– Thus we do not care

• The Y zero point is 23 pixels above the surface

• Thus the Y zero is about a block and half above the floor


Coordinate Diagram


Box Creation

• As we saw in previous presentation the box is created by the addBox method– This is a method of the

ModelRenderer object

• Each box will have an addBox call that sizes and positions it


Unit Cube


public class CurtCubeModel extends ModelBase{ public ModelRenderer body; public CurtCubeModel(){ body = new ModelRenderer(this,20,0); body.addBox(0F,0F,0F,1,1,1); body.setRotationPoint(.5F,.5F,.5F);}

The addBox• The first three parameters are floats

– These are the X, Y, Z positions respectively

• The second three parameters are integers in pixels– Again X, Y, Z respectively– These determine size

• The zero Y will make this thing float in the air– Normally it would have legs or some such

support


Produces This


Commentary

• The unit cube is somewhat in front of the back wall and the camera is above it

• Therefore it looks like it is more like 16-18 Minecraft pixels from the floor


One More Time

• What does the setRotationPoint do?

• Describes the center of the object• When the entity turns it rotates

around this location• By default this becomes 0,0,0

which is a corner• We will now drop the cube to the

floor


Down To Earth


@SideOnly(Side.CLIENT)public class CurtCubeModel extends ModelBase{ public ModelRenderer body; public CurtCubeModel(){ body = new ModelRenderer(this, 0, 0); body.addBox(0F,22.5F,0F,1,1,1); body.setRotationPoint(.5F,.5F,.5F); }

Floored


Commentary• Since the center is set by

setRotationPoint to the cube’s midpoint we must set the Y to 22.5 rather than 23– Otherwise half the cube is below the

floor

• Typically the main body of an entity is the middle of a cube

• Appendages usually specify the joint location– That is where we want it to rotate, not

the middle


addBox Again• The positional parameters define a

corner• The three integers do not define sizes

but distances to travel from the corner– Thus they may also be negative

• Thus we cannot determine which corner the positions specify until we look

• If the Y integer is negative then the positions determine a bottom corner


addBox Again

• We typically want to center the X and Z values and make the Y the height

• Thus if X size is 8 we often make the X position -4– The X then varies from -4 to 4

• If we do this then the item falls into the middle of its shadow


Interlude

• Now we can size and place multiple pieces

• Now we have to connect them• The Minecraft method is addChild• A child maintains its spatial

relationship with the parent as Minecraft moves the parent


Modeling • Two common approaches: • The first is to just build the thing in

Java code• The second is to build it with Techne

and then import the results into Minecraft– http://techne.zeux.me/

• I will do the first– You are free to do either– However, you still need to know the

connection thing


http://techne.zeux.me/

Example• My example will to make an Emu

like entity• It will contain a body, two legs,

head and neck• When that part works we will

animate the legs and head• Three classes:

– CurtEmu– CurtModelEmu– CurtRenderEmu


Process• It is easy to mess this up, so you

should use an incremental approach• Get one thing right, then add the

next– Alas, 30 second compiles slow things

• After modeling is right, animate• You may do textures before or after

animation• I will now abandon the CurtCube

and start developing the CurtEmu


Directionality

• Minecraft must guess as to which end of your entity is front

• The guess it makes is that it is always facing the negative Z direction

• Thus for a cow the Z dimension will be larger than the X dimention

• A crab would be the reverse


Connection• We would like several pieces that

move as one• This is most easily done with the

addChild method• Each new piece becomes a child of

an existing piece• Typically start at the most

important or bulkiest piece and work outward

• For the Emu the body is the center


Body


public ModelRenderer body; public ModelRenderer leg1; public ModelRenderer leg2; public ModelRenderer neck; public ModelRenderer head;… body = new ModelRenderer(this, 0, 0);body.addBox(-3F,10F,-1.5F,3,-3,6); body.setRotationPoint(0F, 8.5F, 0F);

Observations

• The body will be 3 by 3 by 6– The Z is the longest dimension

• It will be positioned 10 pixels from ground

• Y size is negative so bottom corner is origin

• The Y value of 10 puts the body in the air


One more time with addBox

• The coordinates for children are different than the parent

• The parent’s position is relative to the coordinate system

• The child’s position is relative to the parent

• Of course we cannot tell until we do the addChild


The addChild method

• Takes only one parameter:parent.addChild(child);

• See the example in next screen and observe that the new item is relative to the old


Apply the neck


body = new ModelRenderer(this, 0, 0);body.addBox(-3F, 10F, -1.5F, 3, -3, 6);body.setRotationPoint(0F, 8.5F, 0F); neck = new ModelRenderer(this, 0, 0);neck.addBox(-2F, 2F, 0F, 1, 5, 1);neck.setRotationPoint(0F, 0F, 0F);body.addChild(neck);

Notice the 0F for Y position – relative to the body not the regular coordinate system

The Rest

• The legs go below and attach to the body– We will not put feet on the legs, but

could

• The head attaches to the neck• Thus a child may also have

children


Rest of Body


head = new ModelRenderer(this, 0, 0);head.addBox(0F, 2F, 0, -1, -1, -3);head.setRotationPoint(-1F, 0F, 1F);neck.addChild(head); leg1 = new ModelRenderer(this, 0, 0);leg1.addBox(-3F, 5F, 0F, 1, 6, 1);leg1.setRotationPoint(0F, 5F, 0F);body.addChild(leg1);

leg2 = new ModelRenderer(this, 0, 0);leg2.addBox(-1.0f, 5F, 0F, 1, 6, 1);leg2.setRotationPoint(0F, 5F, 0F);body.addChild(leg2);

Doofuss Bird


Modeling Summary

• Not an awful lot of science• Create your boxes and attach

them• The addBox, setRotationPoint and

addChild are the most important now

• The rotation point becomes more important as we animate


Rotation Point

• The animation process works better if the rotation point is properly set relative to the addBox positions

• I found at least three combinations of addBox, setRotationPoint settings that made the head sit properly on the neck

• Only one of them allowed proper turning of the head on the neck


Textures Again• The textures are not applied in the

modeler, but the renderer– CurtModelEmu and CurtRenderEmu

respectively

• Rather there is just one texture and it must be used by all parts– This may have changed before or

after 1.7 for I have seen other ways

• The trick then is to use offsets in a single png file


ModelRenderer• The constructor comes in several

forms• First parameter is always the parent

ModelBase– In most of our code that will be this– A self reference

• One– Second parameter is a string name

• Other– Second and third are offsets


Three Parameter

• Signature ModelRenderer( ModelBase m, int xoffset, int yoffset);

• Example:body = new ModelRenderer( this,300,300);

• We will see this in the next screens


The Graphic


• This is a 512 by 512 png file

Textured


Interlude• Minecraft only moves the main

object• It does this based on what it thinks is

front• It moves in a semi-random motion• Now we want to move the legs, when

Minecraft moves the whole item• We will see this in an animation

presentation


Conclusion

• We construct the structure from rectanguloid boxes– addBox determines size and position– The setRotationPoint determines

“center”

• We connect them with addChild• Textures are applied in the

renderer• Next: On to animation


Copyright © 2015 Curt Hill Models and Textures Making your entity interesting.

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