Solidworks representation of a lake bottom - how to?

[lardlad00]

Hi All -

I'm trying to model the bottom of a lake (could be any lake, really) in Solidworks. I'm not sure if this is the best place to post the question but I couldn't think of anything better and I think I could really benefit from a couple different viewpoints on how to approach this.

I have been working on this as sort of a hobby on and off for a while and have failed at producing anything.

What is the best source for lake bottom data? Obviously I have found fishing type maps that show the contours of the terrain as if it were a topographical map. These can be imported into Solidworks and traced, but it's pretty high labor stuff and for anything but the simplest of lakes it gets pretty daunting pretty quickly.

If I want to create a smooth representation instead of a stepped topographical style, what approach could I use? Obviously for a simple lake, a sweep or loft could do it, but throw in a couple islands and suddenly it gets a lot more complex

I feel like I'm over-thinking this and I'm just stuck on one thought process. Could anyone expand my thoughts?

Thanks!

 

[Eltron]

If you're trying to model an exact replica of topo data then you're stuck with creating the contour sketches. You can try to loft between them, but I would look at using surfacing to do it. You'll be limited by the 1000 meter cube drawing space as well. If you don't particularly care about the exact topo data then you can probably get close with freeform surfacing.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[drawoh]

lardlad00,

The company I work for makes lidar bathymeters. We use software to map river and harbour bottoms. Most lakes are a little deep for us.

The big thing about SolidWorks is that it is parametric, a quality completely useless for what you are doing. There software out there specialized for converting point clouds into surfaces and solids.

A very long time ago, I wrote a program that generated randomm 3D maps. I was able to display these as a wireframe using Borland Turbo_C.

What is it you are trying to do?

JHG

 

[ctopher]

For a hobby, maybe it doesn't have to be accurate?
Some agencies may have data to send you.

To model the lake bed, create a part, then use the Freeform tool.
Without photos of what the floor looks like, someone would know its accuracy.

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

[lardlad00]

Thanks for the replies everyone.

What I'm doing is hoping to make some models of lakes for some friends and family who live on them using my CNC router.

I'm looking to do it in Solidworks because that's what I have access to, as well as Mastercam for the carving. I know it's not ideal for the project, but it's what I have and what I know so I'd love to make it work. If I use another software package it'll have to be cheap or free or it's just not worth it for me.

So, exact scientific replica is not needed at all. I'm looking to make good size models though so a little detail would be nice, but I'll probably be sanding everything smooth when all is said and done anyway so that right there will remove a great deal of accuracy - it's mostly decorative curiosity type of stuff.

What do you think the best way would be to take a topo style map and covert it into a point cloud? If I make sketches with points in Solidworks and export as STL, can I use that data in something like MeshLab to make the surfaces and go from there? Point cloud data is available for some really popular lakes, but I'm looking more at smaller lesser known lakes where topo maps by the DNR are about the best data available, at least to my knowledge.

 

[handleman]

You can't see the bottom of the lake... Just make something up. Nobody will know. >

-handleman, CSWP (The new, easy test)

 

[tristram]

If you have a topo map and can scan it or get it in a digital format and insert that map image on to a sketch plan.
Then create as many planes as needed at the different depths that the topo map has. On each of those planes trace the corresponding contours with a closed spline.
Then create a loft between them to get the surface of the lake bottom (might have to close up the bottom).
Then all you have to do is incorporate that into what ever wood block shape you are using.
You might have to do a scaling operation to get to the size you want.

-Joe
SolidWorks 2009 x64 SP 5.1 on Windows XP x64
8 GB RAM - Nvidia Quadro FX1700

 

[tristram]

If you need islands repeat the procedure for the island and trim the surfaces.


-Joe
SolidWorks 2009 x64 SP 5.1 on Windows XP x64
8 GB RAM - Nvidia Quadro FX1700

 

[rstupplebeen]

I would insert the picture on the top plane and call that thee water level. Trace isoclines that you want to use such as every 5th one. Then offset the top plane by the distance of the isoclines. I would use the full depth and resolution of the map. Now rename all planes (10ft...) otherwise you will get confused at some point. Now create sketches on the planes and convert all isoclines associated with this depth. After you have a significant feature then you can create surface bodies with fills and boundary surfaces.

I hope this helps.

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[rstupplebeen]

Quick and dirty. Please see attached.

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[ctopher]

Looks like a dry, deep, lake.

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

[drawoh]

lardlad00,

If you are programming a CNC machine, you want a contour map, not a point cloud.

What I do with vector graphics programs is scan the graphic and import it as GIF, JPEG or PNG. Then, in the vector graphics program, I trace over it to get a vectorized copy. This will be easiest way to capture vector data, unless you know somebody with a copy of your map in AutoCAD.

I belive you can dump point clouds out to stereo laser lithography machines -- probably not directly, but you can dump them.

JHG

 

[cpretty]

I had a quick attempt at this a while ago and this is the approach I took.

Scan the map (or use an electronic copy).
Insert into solidworks so it can be traced.
Create a plane and label for each contour line.
Trace the contour line onto it's appropriate plane.

This is where I differ from a lot of the previous suggestions in that I don't mind having discrete steps between contours and think it actually makes for a more visually interesting surface.

I first work on creating the water in the lake. Extrudes seem to work better than cuts for this.

Extrude each countour shape to the next plane. You may need to use the area select tool to acheive the correct area.
Use combine subtract to obtain the bottom.

If you have enough contour lines you should get a reasonably smooth surface. You can also obtain more smoothing if you then machine with a reasonably large ball nose cutters and it will add some default radiusing to the stepped model. A bit of sandpaper and it will be smoothed, but not unrealistically so.

Attached is a quick and crude model for you to see the process.

Hope this is of some help. Unfortunately now that you have mentioned this all of us with access to a CNC will have a go.


Craig Pretty

 

[KENAT]

If you did a lofted extrusion rather than a simple extrude wouldn't it do a smoother job?

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[lardlad00]

Thanks again for the replies everybody.

The methods being mentioned for digitizing the maps are pretty much what I have tried so far - taking scans of maps and tracing them in Solidworks with different depths at different planes. Making vectors is tricky because the maps are generally low quality PDFs and cleaning them up enough to work with vectorization doesn't really pay off over just tracing them with splines.

I'll have to try some more work with surfaces to make everything smooth, though I like cpretty's point about using a ball nose cutter to do most of that. I could put a fillet on all the sharp edges and then sand the rest of the way (though I can't see the file due to old version). I'll work on a representative lake and post here if I come up with a decent model.

 

[rstupplebeen]

If you hit a problem area post your model and I'm sure someone will have a look. What version of SWx are you on?

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[rstupplebeen]

ctopher is this better?

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[ctopher]

Very nice!

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

[Guest0527211403]

Not quite a suggestion for Solidworks, but given your application I'd recommend you take a look at Sketchup, in particular the "Sandbox" toolset. It has utilities for converting topo map data directly into contours (although the scanned maps still need to be traced into a vector format). If you have the pro license (a few hundred $$) you can also export this data to other CAD formats for CNC.