Dolphin ?

[Steven P]

Good afternoon,

Looks like I am going to be grounded for a couple more weeks (In the UK), time to amuse myself. 

 

I am looking for a 3D solid dolphin or similar for a bit of a personal project, my plan is to slice it up in CAD, transfer each slice to pieces of pallet wood to make a garden ornament (Thinking about trying to get it in the house, chance varies from none to zero)

 

So the question, is there a website where I can download something like that? Or if anyone has any similar models, both would be much appreciated. I don't do a lot of 3D cad, don't have anything set up to convert anything much either. I found some models before but couldn't make a solid out of them (some details missing), so ideally looking for something fairly simple.

 

Doesn't have to be a dolphin but that was my first idea - anything would work I reckon

 

Many thanks in advance, and if there is nothing out there, I will just fond something else to amuse myself.

[steven-g]

Here you are nearly 2000 to choose from. You will have to find the free ones and then in a format you can use. Yeggi is a collection of 3D models from all over the web

[Steven P]

Thanks Steven-G, I'll take a look.

 

[BIGAL]

Look at stl files but note you can not direct import need a convertor to dwg but lots of free ones out there.

 

 

[Steven P]

Bored so I just drew one....

dolphin_1.dwg

[ammobake]

LOL Cool.

This is kind of how I used to model aircraft in 3D.  It's interesting because these projects can challenge you in ways you don't expect.

 

My first step is to find the plans online with cross-sections of the complete aircraft at specific intervals.  There are some online for like F16, B1 bomber, some propellor craft, etc..

My center line would be a polyline - typically denoted in the cross-sections with a cross symbol.

 

The center line is basically like the master line that controls where everything else gets placed and modeled.  In a 3d context it represents the "spine" of the model and it never changes.

 

In cases where u have a basic sketch type depiction with cross sections A-A, B-B, etc.. you can scale the image or PDF to 100% in autocad.  THEN use some basic linework as location reference for your cross sections.

 

But this is why I really like to use the original plans from the manufacturer when possible because the dimensions are generally pretty true.

 

But you can manually model this way off of photos it just takes more work.

 

This is kind of how autodesk's old 3d scanning app used to work.  You would basically walk around an object with your phone and it would take photos - automatically sending those photos to autodesk.  Autodesk had an engine that would crunch the data and spit out a 3d representation of the object or setting - overlaying the visual information as a texture map.  It would get emailed to you after a few minutes.

 

There used to be competitions as to who could get the coolest 3d mappings.  Some people would scan their pets, other people, cars etc..

 

It was kind of like a precursor to how you can now create asbuilt 3d surveys with only aerial drone photos.  Then design your new project in 3D directly on the site - probably more useful for some applications than others lol.  But similar tech.

 

Personally, my manual method is to model hemispherically.  SO for a fuselage, for example, I would model half the fuselage at each cross section and then use a loft command, or ruled surfaces, etc.. And once completed with half the model, mirror everything over.

It sometimes leaves stuff that has to be added later but it's faster.

 

I will usually select a specific method like meshes only and you learn more along the way.

 

I typically will use ruledsurfaces just because with a mesh its easy to control the surface tabulation counts and keep things consistent.  There are sometimes some complex shapes that require some custom 3dwork but usually not many. 

 

For an F16C some examples would be the cockpit, the jet nozzle, the intake, etc..

And you can apply smoothing factors to your solids in situations where u have rough contours where they aren't intended.

 

[Steven P]

Thanks Ammobake,

 

That's my first attempt at anything like this, I made this up from photos online, 2 views of a dolphin, top and side, scaled to be the same length. Drew in a centre line from each view and used the dimensions at intervals to make up ellipses on the centre line, then loft command to fill it all in. I left the ellipses in the file, reckon that you can rotate them to give it a bit of movement and remake the finale model if anyone wants to (I couldn't get construction plans of a dolphin online). I reckon an ellipse works well for organic shapes like animals.

 

I've seen some of the 3d work people do, I have a long way to go to get to that level! Our work has some amazing 3d models being made, with animations and so on - just got to wait for the call from them to put dolphins in the sea now to justify myself this week....

 

For my project now I have the basic shape is to go back to the line drawing, slice the body parts to make up lengthwise cross sections and make it in real life out of pieces of scrap wood.. might post back here with the next stage when I get time to do that.

 

 

Do you ever post your aircraft anywhere by the way, I would be interested for a look?

[Dana W]

Back in the early 70's I used to draw radio controlled scale model airplane plans extrapolated from 3 view drawings of airplanes that had overall dimensions.  There used to be a series of books one could buy at the local hobby shop with different eras of military or civilian planes.  I don't remember anything about the publications other than they were about letter size and the drawings in them were very well detailed and precise to the scale.  There was no internal details nor any drawings other than the external three views.  The plan view was usually a half & half top & bottom view.  I'd transfer the outline at scale to velum and then add in the parts I'd need to hold the engine, tank, servos pushrods and the like.  The design was with balsawood construction in mind.

 

My most memorable one I did was a P-47 Thunderbolt with the "razorback" cockpit configuration, my all time favorite WW II fighter.  It was one of only two I ever built from my own plans and the most successful one in that it actually flew very well.  Damn, that was almost 50 years ago now.

 

I remember marveling at how easy the center of gravity was to get right.  Very little weight was needed to balance it out of being nose heavy.

Edited February 24, 2021 by Dana W