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Idiot DTM question


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So created a DTM from a 15mb 3d poly dwg file. Translates pretty quickly and not unmanageable. Its mountains and a lake. Model seems to work. Is there a way to lose the smooth green of the water surface? fake it with a floor slightly above the water level contour? Pat?1870645776_ScreenShot2022-06-12at6_49_43PM.thumb.png.ca4d1b38ef46477554c8e046afd9e3a1.png

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Except an extrude won't show rendered in Top/Plan.  I think two's idea of a slab or floor as a hybrid object is better.  

 

If you do the texture bed idea you have to cut out both the shoreline and around any Islands or it will run the texture over the islands.

 

If you make the slab oversized, you can actually show different water levels just by nudging the slab up or down. 

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Thanks everyone. Floor works except oddly, floor in 3D downsizes to a smaller rectangle (first image). In plan its as large as the DTM (second image). that's a new one. the dtm is in as a referenced viewport.  All on a design layer at the same scale. Any ideas? Would be nice if this software would just work.

Screen Shot 2022-06-12 at 8.34.20 PM.png

Screen Shot 2022-06-12 at 8.36.02 PM.png

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To elaborate on @jeff prince  comment:

Place a 2d rectangle around the entire site and extrude it to a height that places top surface at or slightly above the water level.  Do this in a duplicate file: Site model surface can be used to section the extrude resulting in volume representing the lake water. Copy/paste the water volume object to the project file.  
 

This all gets tricky if representing a river or other course of flowing water. Needs to be done in segments of each slope. Extrude is from side based on section along the fall line instead of from layer plane.

 

If representing seasonal or tidal flows, make several separate volumes based on flow data.
 

-B

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13 hours ago, Pat Stanford said:

Except an extrude won't show rendered in Top/Plan.

Well, that's not true.

Extrudes work great, in top/plan, perspective, and clip cube.

You can even use the contours as a basis for the extrusions when you need to be precise.

 

Top/plan

2075368692_ScreenShot2022-06-13at9_57_22AM.thumb.png.0842abe9a9b5f5afc92aacce7daf893e.png

 

OpenGL with transparency

890246002_ScreenShot2022-06-13at10_00_05AM.thumb.png.ed29ac4ce2fe14e22b3d3f7740d15e62.png

 

Clip Cube showing the lake and ocean as separate objects at separate elevations.

1889128751_ScreenShot2022-06-13at9_59_42AM.thumb.png.aac2c0b4916caab6b13a597f4f5914eb.png

 

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2 hours ago, jeff prince said:
16 hours ago, Pat Stanford said:

Except an extrude won't show rendered in Top/Plan.

Well, that's not true.

Extrudes work great, in top/plan, perspective, and clip cube.

I have always thought, and just tested, that 3D objects like Extrudes, will only display edges and not fills  in Top/Plan. And that is a large part of the reason that Hybrid objects exist, so you can get filled faces in Top/Plan.

 

Please teach me how to get an extrude to show as filled in Top/Plan.

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Jeff + Pat:

 

Will try the extrude method. its a lake so all flat. The floor behavior is weird. In plan, displays at scale as advertised. In 3D or side view, it shrinks. Like some sort of scale anomaly. 

 

Like the idea of using the last contour at water level to form the extrusion so water not under the mountains.

 

Pat: Using your extrude along a path idea for tunneling. really helps to see how spearing the land reveals how and were to get out the site modifiers.

 

Jeff: never been able to display an extrusion filled in plan view (as pat noted) unless converted to hybrid. I'm all ears if you have a trick up your sleeve. Updates later this afternoon...

 

-J

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5 hours ago, Pat Stanford said:

I have always thought, and just tested, that 3D objects like Extrudes, will only display edges and not fills  in Top/Plan. And that is a large part of the reason that Hybrid objects exist, so you can get filled faces in Top/Plan.

 

Please teach me how to get an extrude to show as filled in Top/Plan.

 

3 hours ago, jnr said:

Jeff + Pat:

 

Will try the extrude method. its a lake so all flat. The floor behavior is weird. In plan, displays at scale as advertised. In 3D or side view, it shrinks. Like some sort of scale anomaly. 

 

Like the idea of using the last contour at water level to form the extrusion so water not under the mountains.

 

Pat: Using your extrude along a path idea for tunneling. really helps to see how spearing the land reveals how and were to get out the site modifiers.

 

Jeff: never been able to display an extrusion filled in plan view (as pat noted) unless converted to hybrid. I'm all ears if you have a trick up your sleeve. Updates later this afternoon...

 

-J


Extrude as autohybrid.   @Pat Stanford I believe you are the one who taught me that trick years ago 😉

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Will convert to autohybrid in a bit. So far so good. Image is crude and nasty but you get the idea. Still designing.  NNA DC-10 on a strafing run for scale...

might drape the dtm with GIS image however this may be a case of the more abstract the better.

 

Thanks for all the help

 

-J

Screen Shot 2022-06-13 at 7.54.54 PM.png

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1 hour ago, jnr said:

Download google earth image, applied as a texture, gives pretty good results, but man, with a landscape this big, attribute mapping tool does not like playing with textures this big. really hard to get dtm and draped texture to line up (if it would work, gets you out of the auto hybrid/water extrusion game). Auguring in, the landforms look like play dough in closer in perspectives (think the more steep the slope, the worse it gets). Going to have to change gears


When using custom textures (images, sketches, slope analysis, etc), you simply size your texture to the same proportions of the site model.  Magically, no fussing with texture alignment.  I learned this the hard way, much like you have 🙂

I’ll have to dig out some examples.  Another trick for non animated renderings is to have textures at different resolutions for the views you need.  Big birds eye renderings can use small textures, close ups of areas can use models cropped just to the area of interest with higher rez textures to speed up operations.  Animation is a different story, and likely better done in a different program.

 

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J:

Interested in seeing examples. I thought I had sized correctly but off slightly. Doesn't help that the reservoir was low in google (below modeled water level!). thanks for weighing in.

 

T: Forgot about the GIS link. Hoping to have time to circle back. Still have to finish the bridge!

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Jeff:

 

Ideas on how to swap out textures at higher resolution for close in views? model is a design layer viewport, the dtm referenced in. existing texture is applied to the DTM before referencing. What's the trick here?

 

-J

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