4hotshoez

Learning Terrain Modification

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I have struggled long with my terrain model. All the training videos that I can find on terrain deal with a make-believe world of terrain rather than the real world with existing contours that need to change. It could be that Chief is very capable modifying existing contours, but I have not found a smooth and easy way. When I say make believe I am referring to a simple rectangular terrain perimeter with a few simple straight lines to indicate a hill or a valley, which is easy to modify as long as all your hills and valleys are parallel. In the world I live in, the contour lines wander around the site. I have been successful in creating an existing 3D terrain model. But when I attempt to change it with various terrain tools, the model is not smooth, and has waves as it tries to re-conform to the existing contours. It does wacky stuff. I know what I want it to look like in the end, but struggle to get it there. Any suggestions on training or maybe this is a weakness in Chief?

 

Attached plan is X7

post-2194-0-26565600-1455055578_thumb.png

KingPlan05+site.plan

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The thing about terrain is to keep it as simple as possible. When you import terrain data from an outside source often times the resulting terrain plane is so complex that most PC's or Mac's cannot parse it per second in camera views (too complex and two many 3D Faces). What I commonly do is to import a terrain as an image or .dwg and then selectively hand draw-create terrain splines over the indicated contour lines. Where the exactitude of the terrain is not critical I often use elevation planes for large areas. You add a terrain elevation object and then check that change in some camera views, checking each time a change is made so errors can be corrected before several are made causing a real problem to straighten out afterwards (when you goof it sticks out like a sore thumb).

 

DJP

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Todd,

 

Why do you have a Terrain Break around the house?

Let me know if you want to do a Skype session.

It's way too hard to describe by messaging.

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The idea of a terrain break was to reduce the amount of existing terrain would be automatically modified while I added modifiers around the house. It would seem easier to print out the site with contours and draw by hand the contours the way I want them to be then scan them and build them from the 2D scan. I was hoping for some help with cut and fill data from CA.

 

I have been playing with hills to build the terrain around the house and it was looking good until I opened the file again today and now it looks like wavy sand dunes.

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Todd,

 

I think that you are not understanding what the various tools accomplish.

The Terrain Break is used like a retaining wall to place vertical or near vertical changed of height in the terrain.

 

I have never used a Terrain Break like you indicate and I really don't think that it is doing what you want it to do, or what you think it will do.

I would delete it.

 

You then need to add Elevation Lines or similar to shape the overall terrain.

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Todd, take Glenn up on the Skype offer, believe me it will really help. Zip the plan or put it on cloud and send it to him to give him a few seconds to play with it, I believe it will be time well spent. Be prepared for the time difference though, it's a killer!

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Start off with just a few key contour lines.  Then add a flat region for the house - assuming that you want a flat building pad.  Add small flat regions at other locations to get smooth transitions from sloped to flat.  Finally, add raised or lowered regions if needed.

 

Play with this concept on a simple plan so you get the idea.  It's really the easiest way to do terrain.

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Bob, the plan is attached in my first post. I would like to Skype, but I barely have 30 minutes in a 16 hour day for the time being. I am too busy to learn or sharpen the tools as they say.

 

Glenn, I do understand the use of a Terrain Break. I should be able to do whatever I want on either side without effecting the other. And so it works well the way I use it. But that is not the problem as the problem I have began long before I started using the Terrain Break. Chief is desperately trying to keep my contoured terrain even when I modify it. When I rebuild the terrain I get violent waves in the modified area. The Reference manual ends with adding Terrain contours by importing data, but ends there and says nothing about editing or modifying such terrain.

 

I may have too many data points for Chief to make smooth modifications, but how can I know that. <rant> There are many mysteries that remain unanswered and undocumented that only Chief Gurus can answer. I am sure a book could be written just on Chief Terrain or another on Chief lighting, textures and raytracing, not to mention many other tiny secrets that frustrate less seasoned users. So yes, I am frustrated. I am frustrated at nearly every turn. I do very much appreciate the dedication of many gurus who have been offering generous help, which is about the only thing that keeps me paying the SSA. So thanks.

 

It will take me some more time to respond again, because I cannot find a break to get back on here. Skype would be great, but so would some decent documentation.

 

Glenn, I am on Eastern USA time. What part of my clock are you usually available?

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Todd,

 

I am UTC+10 - Canberra, Melbourne, Sydney

I am usually available after 12 noon into the evening.

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Todd,

 

One  thing (well, a couple of things) that I noticed about your plan was regarding you Elevation Lines.

It looks like you have imported them from a survey onto the TOPO layer.

But..... the problem is they consist of a lot of short section lines that often have gaps between the sections. 

This could potentially cause several problems.

One is that there are more elevation points than there need be.

I think Chief uses an Elevation Line to string together Elevation Points at about 24" centres.

With Linear unchecked, you get the warning message about the number of elevation points.

In my opinion, Linear is not the most desirable setting for smoothing (there is no smoothing).

In certain cases, the gaps in the lines could cause their own problems with terrain interpolation and generation.

There are many sections of Elevation Lines outside of your Terrain.

I believe that Chief uses all these points when building the Terrain (even though they are outside the Terrain), slowing the terrain building down.

 

I would firstly get rid of the Elevation Lines outside of the Terrain.

I would then draw continuous Elevation Lines or Splines over the Terrain area only.

That would then be my starting point.

 

Why are the Elevation Lines at odd heights - ie, 8 1/2", 20 1/2", 32 1/2", etc. - no real problem, it just seems a bit unusual.

You could use the contour Offset option to align Chief's contours with the Elevation Lines if you wanted to.  

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Why are the Elevation Lines at odd heights - ie, 8 1/2", 20 1/2", 32 1/2", etc. - no real problem, it just seems a bit unusual.

You could use the contour Offset option to align Chief's contours with the Elevation Lines if you wanted to.  

The 3D topo info was created using Google Earth, imported to Sketchup, Exported as DWG and Imported by crossing my fingers. I have no Idea about the fractional elevations and I do not know how to change the terrain elevation to a number I want. It may be easier to set point elevations or splines by referencing a 2D CAD of the contours or just reference the lines on the TOPO layer. What method of data input will be the best Splines or points?

 

I was not aware that Chief depended upon the lines on the TOPO layer. I was going to delete them but forgot. Can I delete them? I erased the extra ones outside the Terrain.

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Todd,

 

The Topo lines are the elevation data information that Chief uses to shape the terrain.

If you delete that information, you will end up with a flat terrain.

Better to use Elevation Lines or Elevation Splines than points - it is much, much easier to control the terrain with lines than trying to control individual points - that would be like trying to herd cats.

 

To clean things up and to get things working, I think you need to trace over all the Topo lines with new Elevation Splines. On a fairly regular site like that, you could probably get away with tracing only every second or third contour - it shouldn't take too long.

 

I still think that you don't understand the purpose of the Terrain Break and that you are using it incorrectly.

I would delete it - although it doesn't appear to be doing much at all. Using a Terrain Break is the same as using a Retaining Wall.

A Retaining Wall is just a wall with a Terrain Break attached to it.

 

Ideally, what do you want your terrain elevations to relate to?

Sea level (real world), floor level, assumed datum....?

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Todd:

 

Did a video on just that about two years ago -- result is that there is no native capability in Chief but can be done using macros and slices.

 

Final result -- like most macro usage in chief -- was that it's more trouble than worth. -- Use a external cut/fill software.

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