3d Cloth Physics?

Blitz3D Forums/Blitz3D Programming/3d Cloth Physics?

Gabriel

(Posted 2005) [#1]

Does anyone have a sample or a rough guide on handling this? I suppose I could use a physics engine, but perhaps it's overkill just for a simple cloth? I'm also wondering about updating the mesh. Seems like vertexcoords can be pretty slow, but I can't really see an alternative. I suppose I could take a leaf from the book of the guy who wrote the water demo and prerender the animation, tile and animate only the reacting section. It might be convincing enough at a distance. It's pretty limiting though.

Paolo

(Posted 2005) [#2]

When I'm testing my code tend to be a mess,
but may be this can help.

What you see here is basically the relation the
vertexes of a mesh should have between them to move
as in cloth simulation,

use arrows to move the system

Graphics3D 640,480,16,2



Function interpolate#(v#,a#,b#,c#,d#)
Return c+(((v-a)*(d-c))/(b-a))
End Function

c1=CreateSphere()
	PositionEntity c1,-10,-7.5,15
Dim c1f#(3)

c2=CreateSphere()
	PositionEntity c2,-5,-7.5,15
	EntityColor c2,255,0,0
Dim c2f#(3)
	
c3=CreateSphere()
	PositionEntity c3,0,-7.5,15
	EntityColor c3,0,255,0
Dim c3f#(3)

c4=CreateSphere()
	PositionEntity c4,5,-7.5,15
	EntityColor c4,0,0,255
Dim c4f#(3)

c5=CreateSphere()
	PositionEntity c5,10,-7.5,15
Dim c5f#(3)

cam=CreateCamera()
	PositionEntity cam,0,0,-20

fps=CreateTimer(30)

mesh=CreateMesh()
s=CreateSurface(mesh)
	AddVertex(s,EntityX(c1,1),EntityY(c1,1),EntityZ(c1,1))	;0
	AddVertex(s,EntityX(c1,1),EntityY(c1,1)+1,EntityZ(c1,1))	;1
	AddVertex(s,EntityX(c2,1),EntityY(c2,1),EntityZ(c2,1))	;2

	AddVertex(s,EntityX(c2,1),EntityY(c2,1)+1,EntityZ(c2,1))	;3

	AddTriangle(s,0,1,2)
	AddTriangle(s,3,2,1)
EntityFX mesh,16



WireFrame 1
While Not KeyDown(1)
	WaitTimer(fps)

	If KeyHit(28)
	vert=vert+1
	EndIf
	
	If KeyDown(200)	
	c1f(1)=c1f(1)+.1
	c5f(1)=c5f(1)+.1
	EndIf
	If KeyDown(208)	
	c1f(1)=c1f(1)-.1
	c5f(1)=c5f(1)-.1
	EndIf
	If KeyDown(203)	
	c1f(0)=c1f(0)-.1
	c5f(0)=c5f(0)-.1
	EndIf
	If KeyDown(205)	
	c1f(0)=c1f(0)+.1
	c5f(0)=c5f(0)+.1
	EndIf

;	TranslateEntity c2,(((EntityX(c1)+5)-EntityX(c2))/20),((EntityY(c1)-EntityY(c2))/20)-.05,0
;	TranslateEntity c3,(((EntityX(c2)+5)-EntityX(c3))/20),((EntityY(c2)-EntityY(c3))/20)-.05,0

		;Provocar fuerza en C2:
		
;		dist#=1/EntityDistance(c2,c1)

;		vectorX#=EntityX(c2)-EntityX(c1)
;		vectorY#=EntityY(c2)-EntityY(c1)
;		vectorZ#=EntityZ(c2)-EntityZ(c1)

;		vectorX_U#=vectorX/dist
;		vectorY_U#=vectorY/dist
;		vectorZ_U#=vectorZ/dist

;		c2f(0)=c2f(0)-(c1f(0)*vectorX_U*.05)
;		c2f(1)=c2f(1)-(c1f(1)*vectorY_U*.05)
;		c2f(2)=c2f(2)-(c1f(2)*vectorZ_U*.05)

		attract#=.2

		dist#=EntityDistance(c1,c2)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c2)-EntityX(c1)
		vectorY#=EntityY(c2)-EntityY(c1)
		vectorZ#=EntityZ(c2)-EntityZ(c1)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c2f(0)=c2f(0)+(force*vectorX_U)
		c2f(1)=c2f(1)+(force*vectorY_U)
		c2f(2)=c2f(2)+(force*vectorZ_U)

		;-------------------------
		dist#=EntityDistance(c3,c2)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c3)-EntityX(c2)
		vectorY#=EntityY(c3)-EntityY(c2)
		vectorZ#=EntityZ(c3)-EntityZ(c2)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c3f(0)=c3f(0)+(force*vectorX_U)
		c3f(1)=c3f(1)+(force*vectorY_U)
		c3f(2)=c3f(2)+(force*vectorZ_U)
		;-------------------------
		;-------------------------
		dist#=EntityDistance(c3,c2)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c2)-EntityX(c3)
		vectorY#=EntityY(c2)-EntityY(c3)
		vectorZ#=EntityZ(c2)-EntityZ(c3)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c2f(0)=c2f(0)+(force*vectorX_U)
		c2f(1)=c2f(1)+(force*vectorY_U)
		c2f(2)=c2f(2)+(force*vectorZ_U)
		;-------------------------
		;-------------------------
		dist#=EntityDistance(c3,c4)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c4)-EntityX(c3)
		vectorY#=EntityY(c4)-EntityY(c3)
		vectorZ#=EntityZ(c4)-EntityZ(c3)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c4f(0)=c4f(0)+(force*vectorX_U)
		c4f(1)=c4f(1)+(force*vectorY_U)
		c4f(2)=c4f(2)+(force*vectorZ_U)
		;-------------------------
		;-------------------------
		dist#=EntityDistance(c3,c4)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c3)-EntityX(c4)
		vectorY#=EntityY(c3)-EntityY(c4)
		vectorZ#=EntityZ(c3)-EntityZ(c4)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c3f(0)=c3f(0)+(force*vectorX_U)
		c3f(1)=c3f(1)+(force*vectorY_U)
		c3f(2)=c3f(2)+(force*vectorZ_U)
		;-------------------------
		;-------------------------
		dist#=EntityDistance(c5,c4)
		force#=interpolate(dist,0,10,attract,-attract)

		vectorX#=EntityX(c4)-EntityX(c5)
		vectorY#=EntityY(c4)-EntityY(c5)
		vectorZ#=EntityZ(c4)-EntityZ(c5)

		vectorX_U#=vectorX/dist
		vectorY_U#=vectorY/dist
		vectorZ_U#=vectorZ/dist
		
		c4f(0)=c4f(0)+(force*vectorX_U)
		c4f(1)=c4f(1)+(force*vectorY_U)
		c4f(2)=c4f(2)+(force*vectorZ_U)
		;-------------------------

	smooth=40
	gravity#=.1
	
	c1f(0)=c1f(0)+(-c1f(0)/smooth)
	c1f(1)=c1f(1)+(-c1f(1)/smooth)
;	c1f(1)=c1f(1)-gravity
	c1f(2)=c1f(2)+(-c1f(2)/smooth)
	TranslateEntity c1,c1f(0),c1f(1),c1f(2)
	

	c2f(0)=c2f(0)+(-c2f(0)/smooth)
	c2f(1)=c2f(1)+(-c2f(1)/smooth)
	c2f(1)=c2f(1)-gravity
	c2f(2)=c2f(2)+(-c2f(2)/smooth)
	TranslateEntity c2,c2f(0),c2f(1),c2f(2)

	c3f(0)=c3f(0)+(-c3f(0)/smooth)
	c3f(1)=c3f(1)+(-c3f(1)/smooth)
	c3f(1)=c3f(1)-gravity
	c3f(2)=c3f(2)+(-c3f(2)/smooth)
	TranslateEntity c3,c3f(0),c3f(1),c3f(2)
	
	c4f(0)=c4f(0)+(-c4f(0)/smooth)
	c4f(1)=c4f(1)+(-c4f(1)/smooth)
	c4f(1)=c4f(1)-gravity
	c4f(2)=c4f(2)+(-c4f(2)/smooth)
	TranslateEntity c4,c4f(0),c4f(1),c4f(2)

	c5f(0)=c5f(0)+(-c5f(0)/smooth)
	c5f(1)=c5f(1)+(-c5f(1)/smooth)
;	c5f(1)=c5f(1)-gravity
	c5f(2)=c5f(2)+(-c5f(2)/smooth)
	TranslateEntity c5,c5f(0),c5f(1),c5f(2)


	VertexCoords s,0,EntityX(c1,1),EntityY(c1,1),EntityZ(c1,1)
	VertexCoords s,1,EntityX(c1,1),EntityY(c1,1)+1,EntityZ(c1,1)
	VertexCoords s,2,EntityX(c2,1),EntityY(c2,1),EntityZ(c2,1)
	VertexCoords s,3,EntityX(c2,1),EntityY(c2,1)+1,EntityZ(c2,1)
	
	UpdateWorld
	RenderWorld
	
	Text 40,40,vectorX_U+" , "+vectorY_U+" , "+vectorZ_U
	Text 40,60,EntityDistance(c1,c2)
	Flip
Wend

MoveMouse 400,300
End

puki	(Posted 2005) [#3]

Someone once posted a great example - was like a hanging flag cloth - was very good and quick - it doesn't appear to be in the code archives - From memory, they posted it into a thread - I haven't been able to find it. But it might prompt whoever did it to repost it.

EDIT:
I think I am homing in on it - might have good news - need a bit more time.

EDIT:
sniff - "andreas blixt" had a file called verlet3d.zip - However, it is not the one I was thinking of.

poopla

(Posted 2005) [#4]

Verlet will do it just fine, the idea is to cause the position of each vertex to recieve and cause damping on about 8 of it's surrounding vertices. Verlet wouldn't even be needed, but would cover collisions(if you needed it to drape over things etc.

IPete2

(Posted 2005) [#5]

hmm,

I'm not sure this is what you want, but its what I have on my drive, courtesy JFK:

www.smartscreenuk.com/animatedflag.bb

IPete2.

puki	(Posted 2005) [#6]

No, wasn't that one - the other one was a proper draping mesh that had weight to it and you could drag it and stuff - was very good. I reckon I have it on another PC as I tend to horde everything.

Rook Zimbabwe

(Posted 2005) [#7]

Oh Puki... please find it!
-RZ

*	(Posted 2005) [#8]

That one IIRC used a linepick from each vertex in the cloth mesh to properly drap over the mesh, unfortunately it wasnt fast enough (to many picks for a realtime application).

puki	(Posted 2005) [#9]

I FOUND IT!!!!

Use your own texture in the example

PS - WHO WROTE THIS CODE?

Graphics3D 640,480,16,2

ClearTextureFilters

Function interpolate#(v#,a#,b#,c#,d#)
	Return c+(((v-a)*(d-c))/(b-a))
End Function


cam=CreateCamera()
	PositionEntity cam,0,2,-20
	CameraClsColor cam,100,100,100

fps=CreateTimer(30)

AmbientLight 50,50,50

l=CreateLight(2)
	PositionEntity l,0,5,0
	LightRange l,30

Const type_alf=1
Const type_c=2

	
;--------------------------------------------------------------

;------- PLANE -----------------------------------------------

grid=4

alf=CreateMesh()

	EntityFX alf,16
	EntityShininess alf,.75
	EntityColor alf,100,100,50

; PUT YOUR TEXTURE IN HERE - added by puki - 30/3/05
tex=LoadTexture("yourtexture's name",1)
	EntityTexture alf,tex
	
surf=CreateSurface(alf)

v_posx#=0
v_posz#=0

For g=0 To grid
	v_posx=0
	For g2=0 To grid
		AddVertex(surf,v_posx,0,v_posz,v_posx/8,v_posz/8,0)
;		c=CreateCube():PositionEntity c,v_posx,0,v_posz:ScaleEntity c,.2,.2,.2
		v_posx=v_posx+2
		v_index=v_index+1
	Next
	v_posz=v_posz+2
Next

For t=0 To 3
	AddTriangle(surf,t,t+6,t+1)
	AddTriangle(surf,t,t+6,t+5)
Next

For t=5 To 8
	AddTriangle(surf,t,t+6,t+1)
	AddTriangle(surf,t,t+6,t+5)
Next

For t=10 To 13
	AddTriangle(surf,t,t+6,t+1)
	AddTriangle(surf,t,t+6,t+5)
Next

For t=15 To 18
	AddTriangle(surf,t,t+6,t+1)
	AddTriangle(surf,t,t+6,t+5)
Next

For v=0 To CountVertices(surf)-1
	VertexNormal surf,v,0,1,0
Next


Dim vertexes#(CountVertices(surf),3)

lock_vertexs=True

Dim v_collis(CountVertices(surf))

	For v=0 To CountVertices(surf)-1
	v_collis(v)=CreateSphere(4)
		ScaleEntity v_collis(v),.15,.15,.15
		EntityColor v_collis(v),0,255,0
		EntityType v_collis(v),type_alf
		EntityRadius v_collis(v),.15
	Next

v_dumvecino=CreatePivot()
	ball1=CreateSphere(8,v_dumvecino)
	ScaleEntity ball1,.1,.1,.1
	EntityColor ball1,255,0,0
	EntityAlpha ball1,0

v_dumele=CreatePivot()
	ball2=CreateSphere(8,v_dumele)
	ScaleEntity ball2,.1,.1,.1
	EntityColor ball2,0,255,0
	EntityAlpha ball2,0

;-----------------------------------------------------------------------

;-----------------------------------------------------------------------

For c=1 To 1
	cube=CreateCube()
	PositionEntity cube,0,-10,0
	ScaleEntity cube,5,0.5,5
;	TurnEntity cube,0,Rand(-90,90),0
	EntityType cube,type_c
Next

Collisions type_alf,type_c,2,2


While Not KeyDown(1)
	WaitTimer(fps)

;s=GetSurface(test,1)
;	If KeyHit(28)
;	VertexCoords s,v,VertexX(s,v),VertexY(s,v)-2,VertexZ(s,v)
;	v=v+1
;	EndIf
;	TurnEntity alf,0,0,1
	PointEntity cam,v_dumele;alf
;	MoveEntity cam,.1,0,0

	If KeyDown(30)	
	vertexes(20,1)=vertexes(20,1)+.1
	vertexes(24,1)=vertexes(24,1)+.1
	vertexes(21,1)=vertexes(21,1)+.1
	vertexes(23,1)=vertexes(23,1)+.1
	EndIf

	If KeyDown(31)	
	vertexes(20,1)=vertexes(20,1)-.1
	vertexes(24,1)=vertexes(24,1)-.1
	vertexes(21,1)=vertexes(21,1)-.1
	vertexes(23,1)=vertexes(23,1)-.1
	EndIf

	If KeyDown(200)	
	vertexes(20,2)=vertexes(20,2)+.2
	vertexes(24,2)=vertexes(24,2)+.2
	vertexes(21,2)=vertexes(21,2)+.2
	vertexes(23,2)=vertexes(23,2)+.2
	EndIf

	If KeyDown(208)	
	vertexes(20,2)=vertexes(20,2)-.2
	vertexes(24,2)=vertexes(24,2)-.2
	vertexes(21,2)=vertexes(21,2)-.2
	vertexes(23,2)=vertexes(23,2)-.2
	EndIf

	If KeyDown(205)	
	vertexes(20,0)=vertexes(20,0)+.2
	vertexes(24,0)=vertexes(24,0)+.2
	vertexes(21,0)=vertexes(21,0)+.2
	vertexes(23,0)=vertexes(23,0)+.2
	EndIf

	If KeyDown(203)	
	vertexes(20,0)=vertexes(20,0)-.2
	vertexes(24,0)=vertexes(24,0)-.2
	vertexes(21,0)=vertexes(21,0)-.2
	vertexes(23,0)=vertexes(23,0)-.2
	EndIf

	If KeyHit(57) lock_vertexs=Not lock_vertexs
	
	If KeyDown(28)

	VertexCoords surf,24,EntityX(cube)+4,5,EntityZ(cube)
	VertexCoords surf,23,EntityX(cube)+2,5,EntityZ(cube)
	VertexCoords surf,21,EntityX(cube)-2,5,EntityZ(cube)
	VertexCoords surf,20,EntityX(cube)-4,5,EntityZ(cube)
	EndIf

	x#=0
	y#=0
	z#=0

	;**********************************

	;--- change this parameters for testing ----

	attract_force#=.65 	;better not above 1
	separation_dist#=4	;better not under 2
	smooth=12
	gravity#=.05;.075
	
	;------------------------------------------------

	;**********************************

	For v=0 To CountVertices(surf)-1
		Select v
			Case 20
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
;				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
;				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
;				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

			Case 24
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
;				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
;				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
;				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
		
			Case 0
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)

			Case 1,2,3
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

			Case 4
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)

			Case 5,10
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)
			
			Case 15
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

					If Not lock_vertexs
					PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
					PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
					SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)
					EndIf

			Case 9,14
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)

			Case 19
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)

					If Not lock_vertexs
					PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
					PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
					SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)
					EndIf

			Case 22
;				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
;				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
;				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
;				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
;				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
;				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

			Case 21
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

			Case 23
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)

			Case 6,7,8,11,12,13,16,17,18
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-1),VertexY(surf,v-1),VertexZ(surf,v-1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-1,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v-5),VertexY(surf,v-5),VertexZ(surf,v-5)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v-5,separation_dist,attract_force)
				PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
				PositionEntity v_dumvecino,VertexX(surf,v+1),VertexY(surf,v+1),VertexZ(surf,v+1)
				SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+1,separation_dist,attract_force)

				If v<>16 And v<>18
					PositionEntity v_dumele,VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
					PositionEntity v_dumvecino,VertexX(surf,v+5),VertexY(surf,v+5),VertexZ(surf,v+5)
					SET_VERTEX_VELOCITY(v_dumvecino,v_dumele,v+5,separation_dist,attract_force)
				EndIf

		End Select	
	Next

	
	For v=0 To CountVertices(surf)-1
		vertexes(v,0)=vertexes(v,0)+(-vertexes(v,0)/smooth)
		vertexes(v,1)=vertexes(v,1)+(-vertexes(v,1)/smooth)

		;Apply Gravity
		If lock_vertexs=True
			If v<>20 And v<>21 And v<>23 And v<>24
			vertexes(v,1)=vertexes(v,1)-gravity
			EndIf
		Else
		vertexes(v,1)=vertexes(v,1)-gravity
		EndIf		
		vertexes(v,2)=vertexes(v,2)+(-vertexes(v,2)/smooth)
		VertexCoords surf,v,VertexX(surf,v)+vertexes(v,0),VertexY(surf,v)+vertexes(v,1),VertexZ(surf,v)+vertexes(v,2)

;		If VertexX(surf,v)>-5 And VertexX(surf,v)<5
;			If VertexZ(surf,v)>-5 And VertexZ(surf,v)<5
				If VertexY(surf,v)<-9
				VertexCoords surf,v,VertexX(surf,v),-9,VertexZ(surf,v)
;				vertexes(v,0)=0
;				vertexes(v,1)=0
;				vertexes(v,2)=0
				EndIf
;			EndIf
;		EndIf

;		If CountCollisions(v_collis(v))>0
;		VertexCoords surf,v,EntityX(v_collis(v)),EntityY(v_collis(v)),EntityZ(v_collis(v))
;		Else
;		PositionEntity v_collis(v),VertexX(surf,v),VertexY(surf,v),VertexZ(surf,v)
;		EndIf
	Next

;	For v=0 To CountVertices(surf)-1
;		MoveEntity v_collis(v),(VertexX(surf,v)-EntityX(v_collis(v)))/20,(VertexY(surf,v)-EntityY(v_collis(v)))/20,(VertexZ(surf,v)-EntityZ(v_collis(v)))/20
;		If CountCollisions(v_collis(v)) End
;	Next

	UpdateWorld
	RenderWorld
	
;	Text 40,40,TrisRendered()
;	Text 40,60,vertexes(21,0)+" , "+vertexes(21,1)+" , "+vertexes(21,2)
	Text 20,40,"-Use Arrows to Move"	
	Text 20,60,"-Use A and S to MoveUP and MoveDOWN"	
	Text 20,80,"-Use SPACE to toggle gravity"	
	Text 20,100,"-Use ENTER to restore to initial position"
	Text 20,120,"-Use W to toggle Wireframe View"
	
	If KeyHit(17) wire=Not wire WireFrame wire

	Flip

Wend


Function SET_VERTEX_VELOCITY(vecino,ele,vertex,separation#,attract#=.2,newforceX#=0,newforceY#=0,newforceZ#=0)
	dist#=EntityDistance(vecino,ele)
	force#=interpolate(dist,0,separation,attract,-attract)
	
	VectorX#=EntityX(vecino)-EntityX(ele)
	VectorY#=EntityY(vecino)-EntityY(ele)
	VectorZ#=EntityZ(vecino)-EntityZ(ele)
	
	vectorX_U#=VectorX/dist
	vectorY_U#=VectorY/dist
	vectorZ_U#=VectorZ/dist
	
	newforceX=newforceX+(force*vectorX_U)
	newforceY=newforceY+(force*vectorY_U)
	newforceZ=newforceZ+(force*vectorZ_U)

	vertexes(vertex,0)=vertexes(vertex,0)+newforceX
	vertexes(vertex,1)=vertexes(vertex,1)+newforceY
	vertexes(vertex,2)=vertexes(vertex,2)+newforceZ
End Function

MoveMouse 400,300

Who was John Galt?

(Posted 2005) [#10]

Jeez that example looks really complicated! Whats with the massive case statement?

Take a look at the infamous 'Hitman Paper' on the net for some info on modelling cloth.

From your original 'cloth' mesh create two list of types-
points - these hold the x,y,z positions of your mesh vertices
sticks - these link the points and are defined by their rest length - each timestep they modify the positions of the 2 points they connect in a direction perpendicular to the stick, so that the points end up the correct distance apart (stick length) at the end of each timestep. You'll have to update the whole mesh from these positions every timestep, but I'm not sure of the best way to do that- i think vertexcoords are your only option??

its late - may not have explained that well - but can give you some code demonstrating it in 2d if ur interested (in bmax tho).

Paolo

(Posted 2005) [#11]

@Puki,

that code is mine :)
it is basically the same code I first posted here, but
applied in a odd (not optimized) way to each vertex
in the plane... the big code has a dirty way to apply
the velocities for the vertex but there's a function
at the end of the code that could be useful for creating
a generic code to apply "cloth movement" to any mesh...

Paolo.

Rook Zimbabwe

(Posted 2005) [#12]

Paolo... that is some impressive coding!

wizzlefish

(Posted 2005) [#13]

Neat effect, my god!