Site Modifiers

[homero]

7 minutes ago, Tom W. said:

When you ran Send to Surface which option did you choose? 'Fit the retaining edge'? Are you using a Grade Limits as @Jonathan Pickup said earlier?

I've tried both fit and elevate the retaining edge.  Both options gave me modified contours outside of the modifier.  Grade limits creates it's own set of issues.  

[line-weight]

According to this post by @Henry Finch (written 20th Nov 2021 so must apply to vw2022 or earlier) a grade limits object shouldn't be needed:

 

 

 

Have you tried following these steps exactly? That's what eventually worked for me. What was tripping me up was updating the site model too early in the process. It's important to do the "send to surface" bit before updating the site model in any way.

 

 

[homero]

19 minutes ago, line-weight said:

According to this post by @Henry Finch (written 20th Nov 2021 so must apply to vw2022 or earlier) a grade limits object shouldn't be needed:

 

 

 

Have you tried following these steps exactly? That's what eventually worked for me. What was tripping me up was updating the site model too early in the process. It's important to do the "send to surface" bit before updating the site model in any way.

 

 

I finally got it to work by AEC/ Terrain/ Send to Surface/ "Fit the Retaining Edge".   I was selecting "Elevate Retaining Edge".  What is "elevate for if it give less control of the contour lines?

Edited March 14 by homero

[line-weight]

31 minutes ago, homero said:

I was selecting "Elevate Retaining Edge".  What is "elevate for if it give less control of the contour lines?

 

Who knows!

 

The help section seems to be silent on this, and I don't understand the prompts you get when hovering over the options when using the tool.

 

It all needs to be explained much better than it is.

 

 

[Tom W.]

42 minutes ago, homero said:

I finally got it to work by AEC/ Terrain/ Send to Surface/ "Fit the Retaining Edge".   I was selecting "Elevate Retaining Edge".  What is "elevate for if it give less control of the contour lines?

 

That's why I said you need to use 'Fit the retaining edge' 🙂

 

'Fit...' shapes the retaining edge to match the terrain (by adding extra vertices).  'Elevate...' aligns the existing vertices with the terrain with straight sections between them (which is the more likely scenario if you were grading the site around a building for example).

[line-weight]

24 minutes ago, Tom W. said:

'Fit...' shapes the retaining edge to match the terrain (by adding extra vertices).  'Elevate...' aligns the existing vertices with the terrain with straight sections between them (which is the more likely scenario if you were grading the site around a building for example).

 

I struggle to picture what this actually means (I think the only way I'd understand would be doing some trial & error experiments).

 

It really ought to be explained with illustrations in the help documentation. Creating these kinds of level pads with vertical edges is going to be one of the main things any architecture user wants to do, if they start using the site model tool, I think. But as these multiple threads demonstrate, it's very confusing working out how to do what you'd think would be a very simple operation.

[Tom W.]

6 minutes ago, line-weight said:

 

I struggle to picture what this actually means (I think the only way I'd understand would be doing some trial & error experiments).

 

It really ought to be explained with illustrations in the help documentation. Creating these kinds of level pads with vertical edges is going to be one of the main things any architecture user wants to do, if they start using the site model tool, I think. But as these multiple threads demonstrate, it's very confusing working out how to do what you'd think would be a very simple operation.

 

'Fit...' sees the retaining edge follow the surface of the DTM:

 

'Elevate...' sees the vertices of the edge elevated to meet the DTM surface:

[line-weight]

Then in "elevate" there is some kind of interpolation from those straight edges to the site surface some distance away? So I guess it needs a grade limits to define how far away that is?

[Tom W.]

2 minutes ago, line-weight said:

Then in "elevate" there is some kind of interpolation from those straight edges to the site surface some distance away? So I guess it needs a grade limits to define how far away that is?

 

Yes. But we are told from morning til night that modifiers should never be used without a Grade Limits 

[homero]

I fail to understand the benefit of "elevate", but at least I got it to work with "fit".  

[Tom W.]

54 minutes ago, homero said:

I fail to understand the benefit of "elevate"

 

If you were excavating a plot for a building would you expect the contractor to put the earth back exactly where it was originally, following every undulation of the surface, or to grade it smoothly?

[E|FA]

35 minutes ago, Tom W. said:

If you were excavating a plot for a building would you expect the contractor to put the earth back exactly where it was originally, following every undulation of the surface, or to grade it smoothly?

Either one, depending on the situation.

[line-weight]

4 hours ago, Tom W. said:

 

Yes. But we are told from morning til night that modifiers should never be used without a Grade Limits 

This raises the question of why they have to be drawn as separate objects, instead of grade limits being an integral part of any tool that needs them.

[E|FA]

I think it's because you can use a single Grade Limit to control the extent of influence of multiple Modifiers at once. 

Edited March 15 by E|FA

[Jeff Prince]

2 hours ago, line-weight said:

This raises the question of why they have to be drawn as separate objects, instead of grade limits being an integral part of any tool that needs them.

the modifiers and limits have different needs. But if you need your limits to coincide with your modifier, use “create from shape” to make the limits and then do it again to make the modifier, offsetting if you need to.

[Jonathan Pickup]

I wrote a PDF for Henry Finch and it solved his issue. try following the steps I outlined in that PDF: 

 

[Tom W.]

6 hours ago, line-weight said:

This raises the question of why they have to be drawn as separate objects, instead of grade limits being an integral part of any tool that needs them.

 

Also since VW2023 it's possible to have nested Grade Limits. So you can have one Grade Limits defining the site boundary then additional Grade Limits internally.

 

Another way to create them is the 'Create Grade Limits from Planar Pad...' command. Or vice versa using 'Create Planar Pad from Grade Limits...'