irrlicht-newton geometry

[Guest]

hi,
i'm using irrlicht with newton. i couldn't scale down the model using node->setScale because the newton still preserves the original geometry.
how'd i do this with newton?

thanks

[Acki]

You have to create a new Newton body for the node...

[DarkScythe]

not really you need a new body search about :

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NewtonCreateConvexHullModifier

[sudi]

Just change the transformation matrix of the newton body...that will fix it!

[Acki]

AFAIK the tranformation matrix just changes the position of the body, not the scale...

[sudi]

I don't think so but when know it....ok

[Baal Cadar]

Indeed, transformation matrix/offset matrix is solely for rotation and translation, not for scale. For scale use the convex hull modifier.

[Guest]

from api:

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NewtonCollision* NewtonCreateConvexHullModifier(
const NewtonWorld* newtonWorld,
const NewtonCollision* convexHullCollision) 

sorry, how'd i scale it using createconvexhullmodifier?

[DarkScythe]

create sth. like this:

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   NewtonCollision* sphere = NewtonCreateSphere(nWorld, 30, 30, 30, NULL);
	collision = NewtonCreateConvexHullModifier(nWorld,sphere);
	NewtonReleaseCollision(nWorld,sphere);
	body = NewtonCreateBody(nWorld,collision);

and modify like this:

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   dMatrix pmatrix;
	NewtonConvexHullModifierGetMatrix(collision,&pmatrix[0][0]);
	pmatrix.m_up.m_x *= 0.4;
	pmatrix.m_up.m_y *= 2;
	pmatrix.m_up.m_z *= 0.4;
	NewtonConvexHullModifierSetMatrix(collision,&pmatrix[0][0]);

[Baal Cadar]

Note, that the hull modifier is scaled in world space, not in the modified collisions local space.

[Guest]

create sth. like this:

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   NewtonCollision* sphere = NewtonCreateSphere(nWorld, 30, 30, 30, NULL);
	collision = NewtonCreateConvexHullModifier(nWorld,sphere);
	NewtonReleaseCollision(nWorld,sphere);
	body = NewtonCreateBody(nWorld,collision);

and modify like this:

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   dMatrix pmatrix;
	NewtonConvexHullModifierGetMatrix(collision,&pmatrix[0][0]);
	pmatrix.m_up.m_x *= 0.4;
	pmatrix.m_up.m_y *= 2;
	pmatrix.m_up.m_z *= 0.4;
	NewtonConvexHullModifierSetMatrix(collision,&pmatrix[0][0]);

what member is dMatrix?

[sdi2000]

dMatrix is from the Newton sdk.

[Guest]

hum. weird i already linked the sdk, but it says "undeclared identifier"

[sdi2000]

look at ... NewtonSDK\samples\toolBox
include the dMatrix.h

[Guest]

okay yea i got it all compiled now.
but it's still not scaling it.

this is what i have:

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NewtonCollision* myShape = NewtonCreateBox(nWorld, size2.X, size2.Y, size2.Z, NULL);
	NewtonCollision* collision;
	collision = NewtonCreateConvexHullModifier(nWorld,myShape);
	dMatrix pMatrix;
	NewtonConvexHullModifierGetMatrix(collision, &pMatrix[0][0]);
	pMatrix.m_up.m_x *= 0.4;
	pMatrix.m_up.m_y *= 2;
	pMatrix.m_up.m_z *= 0.4;

	NewtonConvexHullModifierSetMatrix(collision, &pMatrix[0][0]);

am i doing it right?
changing the numbers didn't seem to have any effects...