Sandbox- From Contours- Issues

blackdogsketch

Hello. New member,
I've been using sketchup for over ten years.
Started doing some intermediate site modeling recently.
I started with contours, drawn flat, in sketchup. (we do not have survey contours or CAD)
Then push/pulled the "terraces", then deleted the "risers".
then Sandbox/From Contours.
So, it makes the TIN, but here are a few problems.

Despite a lot of cleanup in the contours before running FC, there are still "spikes" or "stalactites" that hang from the underside of the TIN. There's a corresponding "ice cream cone" hole in the upper surface.
I do not see an easy way to rectify these aberrations.
I had thought that I could use the Smoove tool on the TIN once it had been completed. However it seems that this is not really the case. The smoove will work on some flat portions of the terrain but, in general, does not work. Is it usual to create the TIN from contours in this way and how does one "tweak" or adjust the TIN afterwards?
I noticed that I must be inside the group of contours in order to run the From contours tool. And that the TIN is created on the same layer as all the contour elements. Makes it more challenging later. Is it possible to keep the contours and the TIN on separate layers?

4 Any addition advice on this topic would be appreciated.

Thanks

pbacot

@blackdogsketch said:

Hello. New member,
I've been using sketchup for over ten years.
Started doing some intermediate site modeling recently.
I started with contours, drawn flat, in sketchup. (we do not have survey contours or CAD)
Then push/pulled the "terraces", then deleted the "risers".
then Sandbox/From Contours.
So, it makes the TIN, but here are a few problems.

Despite a lot of cleanup in the contours before running FC, there are still "spikes" or "stalactites" that hang from the underside of the TIN. There's a corresponding "ice cream cone" hole in the upper surface.
I do not see an easy way to rectify these aberrations.

I had thought that I could use the Smoove tool on the TIN once it had been completed. However it seems that this is not really the case. The smoove will work on some flat portions of the terrain but, in general, does not work. Is it usual to create the TIN from contours in this way and how does one "tweak" or adjust the TIN afterwards?

I noticed that I must be inside the group of contours in order to run the From contours tool. And that the TIN is created on the same layer as all the contour elements. Makes it more challenging later. Is it possible to keep the contours and the TIN on separate layers?

4 Any addition advice on this topic would be appreciated.

Thanks

Hi Welcome to the forums.

When you erased the risers, are you left with one contour at each elevation? The way I often work with contours is just (Move) raise them up to their level, one by one. When I create the surface with SB I can select its group (it's created in a separate group), put it on any layer I want. Not sure how it matters what layer it starts on.

The smoove tool can be finicky but should work on the SB surface.

blackdogsketch

Well what I did the first time was erase the "risers" and leave the flat terraces at each level as complete skinned planes. In other words I did not move just the contour lines themselves up on the blue axis. I think I am going to have to try it that way. You can see how SB might be confused with the leading edge of a 28' contour 12" above the back edge of the 27' contour. It's hard to look at the resultant TIN and deciper what may have gone wrong but I am going to try it the second way.

It's had manipulating only the lines! Zooming is very tough without something solid underneath! And, it's easy to get confused which contour lines are which- and which need to be moved a certain distance. All in all, not a pleasant process.

I ahve found the smoove tool to be uncoorperative on the tilted surfaces of the TIN.
Perhaps after I generate it the second time it will be better.

I watched a video by Danial Tal at Basecamp 2012 and he advocated a RubyScript called Simplify Terrain. That turns the TIN with triangles into a grid "TIN" of rectangles. Which smoove likes better...and also a RS called Artisan, which is a much better "smoove" kind of tool(s).

going to take some time to figure this all out.

panixia

you should definitely take a look also to toposhaper and vertex tools plugins for this kind of job..

blackdogsketch

If anyone can point me to a You tube or other tutorial on this process, I would be most grateful.
After running SB/From Contours, there are these odd artifacts (upside-down cones projecting from the underside of the TIN) ...also of course, this is a cone-shaped hole from the top of the TIN.

But I need to understand the whole concept more.
Obviously if you have contours, you raise them to the appropriate elevations, and then add the TIN via SB/FC.
But what about retaining walls, steps, existing buildings at various elevations???

Do you have to model building walls and draw contours against them?
Do you create groups of retaining walls first, then draw contours against them, and then turn them off before making the TIN?

pbacot

Yes group the retaining wall entities. You might use "Tools on Surface" plugin to draw your profile on the group, but not necessary. The group should not affect the SB from contours process.

I like to make curves of the contours with recurve rb. The process will also assure you've got a continuous set of segments for each contour. You can also use simplify curve routines (Fredo Tools?). But definitely look at Toposhaper that resolves some these requirements. There should definitely only be the single contour set, not a flat surface or second set below.

To raise the contours from a flat set, there are various methods, You might make a vertical array of edges or guides to snap to your intervals. I think the push-pull method is more trouble.

Look for Daniel Tal's 2008 lecture video too. You will see more on SB work.

https://sites.google.com/site/3dbasecamp2008/