Change the height of a cylinder? Progress bar - Like

I having problems to change the height of a cylinder with its base clamped on the ground (because its reference point is located at the center of the cylinder) it is very difficult by using llSetScale (because I need to change the Z position and Height, and the minimum height is 0.010 and not 0).
I was trying to use llSetPrimitiveParams with PRIM_TYPE and PRIM_TYPE_CYLINDER with no results. I need to control the height of the cylinder just like a "Windows Progress Bar" from 0% to 100%.
Can anyone help me?
thanks in adavance

Something like...

vector size = < ... >;
vector pos = < ... >;

llSetPrimitiveParams ([PRIM_POSITION , pos, PRIM_SIZE, size]);

...will set the position and size with one call.

The position is for the center of the prim so you'll probably want to update .z position based on half the height. Like, if you want the bottom to be at position.z =50.0, set position to be 50.0 + (size.z / 2.0).

Untested but probably close...

Take a look at http://wiki.secondlife.com/wiki/Curtain_script for an example of how to do this with Meade's method, and try changing the offset to offset.z rather than offset.x.

Though since you've got the problem of moving it from 0.0, " and the minimum height is 0.010 and not 0", it might be simplest, depending on how long the progress bar is, to bury it so the top of the un-extended cylinder is flush with the ground -- i.e. the centre point is just below the ground -- and let it grow in both directions.

Another option is to keep the prim the same size but mess with the texture offset..

Just had a quick play and E slice can take the height down to nearly 0 without moving the prim. Maybe just change that in script?

One nice thing about slice is the texture does not move so you could have a graduated texture or green/yellow/red to indicate measure say and not have it mess up.

Rime

Unfortunately, you can't slice stuff with llSetPrimitiveParams, which I agree would be a very neat solution to a lot of problems if only you could. See http://jira.secondlife.com/browse/MISC-2847

Yes Rime, I was thinking in the E slice (to take the height down to 0 without moving or changing the main-height of the prim). But I can't do that using scripts (the function llSetPrimitiveParams seems not having that feature).

Ahhhh, yes, well... that would be a bit of a issue then. Tried to vote on the Jira but getting page not found. Will go vote later.

Rime

It's a bit more complicated but couldn't you change the prim type to something that slices, set the slice then change it back to a cylinder all in the same call?

Here you go:

/54/9b/288343/1.html

apparently no... they've quietly updated the primitive params call so that changing type wipes out (or at least defaults) params they haven't included... there's a jira (I was VERY surprised to find that issue, and more than a little pissed off)

/me blinks. Wow...

Wonder how much content that broke.. Or is one of those things that just happens on a recompile?

This is from the thread i referenced. A candle that burns at a set rate. You will notice that you have to adjust scale and then set pos by 1/2 the scale adjustment.

integer on = 1;
vector startscale;
vector startpos;
float meltpercent = 0.1;
float melt;
vector move;
float delay = 0.5;

startover() {
	llSetScale(startscale);
	llSetPos(startpos);
}

default {
	state_entry() {
		startscale = llGetScale();
		startpos = llGetLocalPos();
		melt = startscale.z * meltpercent;
		move = <0.0, 0.0, melt >;
	}
	touch_start(integer total_number) {
		if (on) {
			llSetTimerEvent(delay);
		}
		else {
			llSetTimerEvent(0.0);
			startover();
		}
		on = !on;
	}
	timer() {
		vector scale = llGetScale();
		if (scale.z <= melt) {
			startover();
		}
		else {
			llSetScale(llGetScale() - move);
			llSetPos(llGetLocalPos() - (<0.0, 0.0, melt / 2 >) * llGetLocalRot());	
		}
	}
}

Cool! That is from when Ruthven was just learning here. From total noob to Scripting Forum God in just a few short months

lmao, i hardly think i'm a scripting forum god, i still have LOTS to learn. and i took a bit of a break from sl and forgot a lot of what i learned lol. when writing scripts lately, i'm constantly checking the wikis and the forum for examples to help me understand functions better.

And modest too!

Thank you friends for your invaluable help.
I'm using this solution and works fine:

llSetPrimitiveParams with PRIM_SIZE and PRIM_POSITION

probably not much content per se (not many people willing to jump through that hoop on a regular basis), but prim torture? completely out the window =(