Issue with pre-scaled object as camera parent

Blitz3D Forums/Blitz3D Programming/Issue with pre-scaled object as camera parent

R0B0T0

(Posted 2004) [#1]

When I use a pre-scaled object as a parent for a camera, why does it affect the perspective? Here is an example:

Graphics3D 640,480,16,2
SetBuffer BackBuffer()

cam = CreateCamera()
PositionEntity cam, 1, 5, -4
RotateEntity cam, 50, 0, 0

box = CreateCube()

ball = CreateSphere()
PositionEntity ball, 3, 0, 0
ScaleEntity ball, .25, 1, .25

EntityParent box, ball
;EntityParent cam, ball

While Not KeyDown( 1 )
	RenderWorld 
	Flip 
Wend
End

If you run the code, notice that the box is being parented by the scaled ball, and it's dimensions are not affected in anyway.

However, if you uncomment the entityparent line with the camera, suddenly the camera perspective is affected by the scaling on the parent object.

Can anyone explain this?

DJWoodgate

(Posted 2004) [#2]

Try turning the box. Entity Scaling is inherited from the parent. Scaling the mesh of the ball using scalemesh might be what you are after.

Shambler

(Posted 2004) [#3]

I had a similar problem, I ended up creating another pivot and then parenting both the scaled mesh and the camera to it to avoid the camera getting scaled.

_PJ_	(Posted 2004) [#4]

Graphics3D 640,480,16,2
SetBuffer BackBuffer()

cam = CreateCamera()
PositionEntity cam, 1, 5, -4
RotateEntity cam, 50, 0, 0

box = CreateCube()

ball = CreateSphere()

ScaleEntity ball, .25, 1, .25
cball=Copyentity (ball)

PositionEntity cball, 3, 0, 0
EntityParent box, cball

EntityParent cam, cball

While Not KeyDown( 1 )
	RenderWorld 
	Flip 
Wend
End

Just curious, and I cannot test this myself at the mo... does this still have the same effect? or even CopyMesh...

R0B0T0

(Posted 2004) [#5]

@DJWoodgate:
Thanks for the clarification, I was confused by the apparent discrepancy in behaviour. It didn't occur to me while comparing that the box wasn't being rotated.

@Shambler:
Your solution is good enough for me. I had already tried adding a pivot as a buffer between the object and camera, but encountered the same problem.

@Malice:
Good question, but since I'm at work I can't test it either :)

_PJ_	(Posted 2004) [#6]

Just tried it -
CopyEntity had the same effect.
CopyMesh, however didn't - any use to you?