# Rotate Function

DELFTship forum Hull modeling Rotate Function

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Posts
• #39112
John Owles
Participant

Hello there,

Does anybody know the definitive method of using the Rotate tool.

I am trying to rotate a propeller along its z axis by 3 degrees and the y axis by -3 degrees. By much trial and error I have managed to rotate along the z axis but I cannot work out how to achieve the -3 degrees or 357 degrees along the y axis.

Any gems would be gratefully recieved.

• #39114
Icare
Participant

The first thing you have to understand is that Delftship make its rotations using the origin point coordinates (0,0,0) as center of rotation. This mean the part must be drawn around this point. If not you’ll get strange moves.

Thus you must move your propeller to the point (0,0,0), rotate it, then bring it back to its place.
An other way is to draw the propeller along in its own file, to save it as a PART. Then you open your ship’s file an IMPORT it: it will appear at the point (0,0,0). Then you just have to move it to its place.

I prefer the second method because it makes the propeller available for other models or you can import it again to get two propellers (or more) on the same model without havig to draw them (daunting task, isn’t it? :pinch: ).

• #39119
John Owles
Participant

Thanks Icare,

Your method seems to be for the original Rotate function. We now have a set of six input boxes into which we enter coordinates. I assume that they define the point of rotation, the equivalent to the original 0,0,0 point.

I did manage to successfully rotated along the z axis for the vertical shaft line but in this instance I also have to offset the shaft line horizontally to 3°. Unfortunately it does not seem to work in the horizontal plane. No matter how I enter the coordinates, it stays stubbornly where it is.

Marven, if you read this, could you give us a clue.

• #39127
John Owles
Participant

I’m still not getting anywhere with the Rotate function.
I am now trying to rotate a mast to rake it aft by 3 degrees. No matter what coordinates I enter into the input fields it either stays exactly where it is or it rotates to port or starboard.

Does anybody know extactly what coordinates should be entered into the input grid to make the Rotate function work?

There does not seem to be anything useful in the manual about the Rotate function and I am heading towards the need for ‘stress councelling’

• #39128
Icare
Participant

Thanks Icare,
Your method seems to be for the original Rotate function.

You’re right, I’m still using an old version.

… I’m trying to guess what I’d try in your situation… :dry:

If your mast is just a cylinder, can’t you re-create it with its angle yet entered in the cylinder creation data? (matter of sinus & cosinus).

Otherwise, if it’s something more complex than a cylinder, can’t you export it to its own file as a ship part, rotate it there, then import if back to the original ship’s file?

• #39130
John Owles
Participant

Your suggestions would certainly be a solution but if I could figure out what enter into the input for the Rotate function it would be considerably quicker. Also the point is that the function is there and, is now in its latest all singing and dancing version, without any comprehensive information about how to use it.

I would have expected an x y z input to provide an origin for the rotaion and an x, y, or z to indicate the plane of rotation.

What we actually have is two sets of x y z inputs one for the start point and one for an end point. While I can understand the Start Point coordinates, I cannot visualise what may be required of the End Point coordinates or how they are connected to an angle of rotation. I can also see that this type of input works for creating a cylinder etc, but for rotation ????! I do also suffer from occasional brain freeze so please forgive me and treat me gently if it is obvious to you.

I have attached an image of the offending input for the Rotation function so you can see what I am banging on about!

I have a thing about stuff that does not work or that I cannot make work. It doesn’t matter that there may be a ‘work around’, still need to get the function or the machine, or what ever it is, working.

I had hoped that Marven or Maarten might pick up on my question and give us the definative method of using the function.

• #39136
Icare
Participant

I checked for the new manual and found there’s no much enlightments. :unsure:

After seeing your screen shot, I imagine you’ve to enter coordinates for two points defining a line (in 3D environment) which will be the axis of rotation. This means the axis of rotation can be aslant, while it could be only vertical, longitudinal or transversal in the previous versions.

I guess that if you enter first the coordinates (x,y,z) of the point of your mast’s foot, then an other fictive point’s coordinates (x,y+1,z) you’ll get a rotation along the transversal axis (forward or backward); meanwhile with (x+1,y,z) coordinates for the second point, you’ll get a rotation along the longitudinal axis (on port side or on starboard); and with (x,y,z+1), you’ll get a rotation along the vertical axis (tack shift… visible only if you include the boom).

This reminds me an other 3D CAD software in which it was possible to click with the mouse on two points to select the rotation axis (kinda way I mentioned just upper) or on three points to define the plane the axis would be perpendicular to… provided these points were already drawn (there was no dialogue box).
Now, Delftship seems to be able to do the first selection mode thru a dialogue box.

It may seem more complex than in previous Delftship’s versions, but it allows more complex rotations using an aslant axis (x+1,y+1,z+1 for example).

I hope all these suppositions are correct and neat (I can use only the old version v.6 on my comptuter and english isn’t my mother tongue) and the thing is pretty complex to explain with no picture.

• #39140
John Owles
Participant

I came to the same conclusion that the first coordinated indicate the location and the second define the axis of the rotation.

So far, regardless of various combinations of axis input, the rotation is always anticlockwise athwartships!

I am thinking that either I am not getting it or there is a problem somewhere that requires advice from Mission Control.

• #39171
John Owles
Participant

Some progress.
It seems that the axis input defines rotation along the given axis, rather than rotaing around the axis. If that makes sense

• #39173
Icare
Participant

It may make sense: It may be a question of directions relative to the origin point (coordinates 0,0,0)… which is always used as center of rotation.

May be the rotation’s center is still the origin point (coordinates 0,0,0), and the coordinates you enter in the dialogue box are the one for a random point’s direction and its new position’s direction after rotation.
For example, if both points are on the same Z coordinate (on an horizontal plane) the rotation will be made around a vertical axis. And if these points form a 90° angle with the origin point as vertex (whatever the distance), then you’ll get a 90° rotation. And it these points are located on each side of the origin point (whatever the distance), you’ll get a half turn.

Is it clear saying it this way? :unsure:
It’s so difficult to try to guess it when I can’t do any trial…

• #39177
John Owles
Participant

The first line of inputs definately define the centre of rotation, with coordinates being relative to the origin (0,0,0).

The second line of inputs seem to define the direction of rotation along an x, y or z axis.
(1,0,0) would rotate along the x axis by n degrees
(0,1,0) would rotate along the y axis by n degrees

I haven’t tried yet but maybe a 45 degree direction of rotation along a combination of x and y would be (1,1,0).

It will be interesting to see whether the direction of rotation can be fine tuned using inputs of o.5 or 1.5 etc.

I need time to play!

• #39487
Anneler Ruedi
Participant

Hi all

I have a similar problem. I’m trying to rotate a tiller (put together from several cylinders and a sphere) alon the y axis by some degrees. I simply do not know how to do this. I think to make all explanations given here so far would be way more understandable if someone could add one or more drawings showing the base part to be rotated, the rotated part, and all the entries needed in the rotate function to make this happen.

I think that graphics are always very valuable for better/correct understanding any textual or spoken explanation 🙂
Text explanations alone create assumptions at the readers side. If the reader’s aussumptions are different from the writer’s meaning, the reader’s try to redo what the writer says will simply not work 😉

• #39489
Anneler Ruedi
Participant

I’ve made a simple box with different colors on all sides to find out how rotation work.
First of all: It works.
Wfhat I found somehow puzzling is the naming of the views in relation to the XYZ axis. It seems to have another logic than in a CAD system.
When looking from the top vertically onto a flat horizontarl workplane in a CAD system “Front” views from me and “Back” views against on the Y axis.
In Delfsthip “Aft” views from the left hand side of the X-Axis, and “Front” views from on the right hand side of the X axis.

When looking from the top vertically onto a flat horizontarl workplane in a CAD system “Left” looks from the left hand side of the X axis, and “Right” looks from the right hand side of the X axis.
In Delfsthip “Left” views against me on the -Axis, and “Front” looks from me on the Y axis.

And Delftship allows to define the Zero Point on the left or on the right side of the X axis.
The use of the views in Delfsthip makes sense, but one should be aware of these different namings of views ;-).

I’m running some test just now with my bx model to find out how rotate really works ..

We’ll see .

• #39490
Anneler Ruedi
Participant

SORRY!

sorry for any confusion, but my last is completely WRONG – so please IGNORE it.

I made some errors by adding the different colors to differnet side of my test cube.
the orientation of delftship (axis and views) is correct as it is.

to have zero x at the stern of a ship allows to show view “rigth” for the starboard side, and *left* for the board side of a ship.

Probably I’ll come up with a new try (and hopefully better one) later on ;-).