# how to design a solid part if i want to fix its volume?

for example i want to make a cylinder of 5 Ltrs. volume. how can i add a formula to keep its volume fixed but i can change its height and radius. i need relativity between its H and r so that if one is varied, the other gets automatically adjusted to maintain the volume to 5L.

Set the height as a formula volume/(pi*dia^2*0.25)

If you have the CATIA Optimizer product, you can use that to find Height or Radius based on the Volume.

But Dom's suggestion is probably easier. Just set up the Parameters and an equation

Assuming you are using millimetres, one litre = 10^6 cubic millimetres.

So if you want your height to be based on diameter (easier), then your formula needs to be:

h = 5 000 000/(pi*d*d*0.25)

where pi is 3.14159....
h is cylinder height in mm
d is cylinder diameter in mm

I could write the formula for SolidWorks but I can't help you with the exact syntax required for CATIA, sorry.

Jack is right. You can use Catia Optimizer...