contact points for ships

[robystar]

Hi all,

I have been working the whole day on trying to get the contact points right for a Russian navy vessel (it is the mousson season here anyway).
The problems are/were as follows:
- First I had to lower the model in the grid with ModelconverterX so as to be able to set the cg height, the wheels, the float points etc. right for the vessel to lie correctly in the water;
- Then I started on the contact points (wheels and floats);
- the vessel stamps and rolls nicely but every 10 seconds or so it jumps up a little (like it has some hiccups);
- those hiccups interrupt the bowspray effect and the wake effect.
Does someone have an inkling what could cause those hiccups?

[robystar]

Well, if I can help somebody with my observations:
It was a matter of estimating the cg height of the model in order to have the cg height and wheels not too low or high (did that with modelconverterx but that program does not give any indication of the coordinates of the various points).
PS I still wonder why the water= (in the aircraft.cfg) has multiple attach(?) points for effects. I know that in some way they are tied to the float contact points but that does not explain why there are more effects visible than there are float points.

[mfitch]

What I learned from other posts about the motion of ships is that the center of gravity and the weight (set in aircraft.cfg) both play a big role in the stability. Increasing the weight increases stability (less pitching) just as it ought to in reality. Setting the CG too low also will cause FS to think the ship has sunk (only applies to pilotable ships). I found no forum entries on formulas for calculating CG, float contact points, and weight. I just played with them until they worked reasonably.

On my ship I only get wake at the three float contact points. More might result from the particular wake effect used. My biggest problem with wake effects was that I needed the float contact points in one set of locations for the ship to float correctly and in different locations for the effects to look right. This can be fixed by editing the wake effects (adding an offset).

Its great to learn someone is working on another ship.

[robystar]

Hi,

Thanks for showing interest. Nice to know I am not the only one.
Guess you know fs-shipyards.org where you can find a lot of vessels.
But it looks as if no one is interested anymore.
I have made a lot of water effects but as they are so specific for each vessel and each use (AI, simobject, pilotable), there is no point in uploading them.

[thatch]

Hi Rob..long time no see mate !! Yes have to agree FS-Shipyards is not what it used to be... I can't even find my way around the Forum these days and hey I still own the Domain Name but I no longer have anything to do with running FS-Shipyards at all.


I know when I made my 1st few ships I had the same Hiccups problems but after playing with the "weight" .. from memory a decreased this it fixed most of my problems.

Cheers
Ian "Thatch" Thatcher

[Trans1007]

Well im still at Fs-Shipyards. Im learning the ADE program to use in building Ports, and why not a Port is the airport for ships.

[robystar]

Hi Ian,

Good to hear from you again as well. How have you been faring after 'leaving' the yard?
Paul(Basys) is doing his best for fs-shipyards and it still is a nice site. I am just wondering how come there is hardly anyone that asks questions there.
I, for one, am sure there are hundreds still to be posed.

Thanks fellows for pointing out the weight and cg as a factor for stability. It does not solve the hiccups though. Maybe it has to do with the damping?

One of the problems of AI ships is that they have to taxi. That is why I switched to the AIBTC type boat routes. But it is more difficult to add effects and lights. Trans1007, what do you use ADE for?

Roby