# Curves display through surfaces differs in V7

**URL:** <https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706>\
**Category:** Rhino for Windows\
**Created:** [January 21, 2021, 6:54am UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706 "2021-01-21T06:54:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![coffsoft](https://avatars.discourse-cdn.com/v4/letter/c/5f9b8f/32.png) [@coffsoft](https://discourse.mcneel.com/u/coffsoft)\
**Post date:** [January 21, 2021, 6:54am UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706/1 "2021-01-21T06:54:41Z")

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Hello,

V7 behaves differently from V6 with regard to curves display through surfaces.

When a curve is selected, it displays with the standard yellow selecion highlight through surfaces regardless of the display mode. That is good, and the behaviour is the same in V6 and V7.

However, after a curve has been the subject of a Bring Forward action, and it is no longer selected, the behaviour differs between V6 and V7.

Even though a curve has been the subject of a Bring Forward action, its position in 3D space relative to surfaces in front should dictate its display according to the selected display mode.

Under V6 before Bring Forward, with the curve deselected:

Mode Curve visible through surface?  
Shaded No  
Rendered No  
Ghosted Yes - OK  
Technical No  
Artistic No  
Pen No  
Arctic No  
Raytraced No

Under V6 after Bring Forward, with the curve deselected:

Mode Curve visible through surface?  
Shaded Yes - probably wrong  
Rendered No - this has been useful, but now lost in V7  
Ghosted Yes - OK  
Technical Yes - probably wrong  
Artistic Yes - probably wrong  
Pen Yes - probably wrong  
Arctic No - this is as I would expect  
Raytraced Yes - probably wrong

Under V7 before Bring Forward, with the curve deselected:

Mode Curve visible through surface?  
Shaded No  
Rendered No  
Ghosted Yes - OK  
Technical No  
Artistic No  
Pen No  
Arctic No  
Raytraced No

Under V7 after Bring Forward, with the curve deselected:

Mode Curve visible through surface?  
Shaded Yes - probably wrong  
Rendered Yes - **this is the one that is annoying**  
Ghosted Yes - OK  
Technical Yes - probably wrong  
Artistic Yes - probably wrong  
Pen Yes - probably wrong  
Arctic Yes - probably wrong  
Raytraced Yes - probably wrong

[CurvesThroughRenderEtcV6.3dm](https://discourse.mcneel.com/uploads/short-url/7JLseINiUQl6IywecPBsdujNbFl.3dm) (41.9 KB)

Regards, Garry.

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**Author:** ![wim](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/wim/32/747482_2.png) [@wim](https://discourse.mcneel.com/u/wim)\
**Post date:** [January 21, 2021, 12:36pm UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706/2 "2021-01-21T12:36:42Z")

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Hi Garry -

> [@coffsoft](#):
>
> V7 behaves differently from V6 with regard to curves display through surfaces.

I see that here as well, yes.

As for the Rhino 7 behavior for the `Rendered` display mode - that appears to have been brought in line with all the other display modes and I suspect that this was an intended change.

A quick search in YouTrack hits only 1 item ([RH-55466](https://mcneel.myjetbrains.com/youtrack/issue/RH-55466)) that seems related and that was a wish that `Rendered` behaved like the other display modes for annotations that are “brought to front”. That seems to now work “correctly” on Rhino 7 but without that YT item having been the source of that change…  
-wim

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<div class="post-metadata">

**Author:** ![davidcockey](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/davidcockey/32/732604_2.png) [@davidcockey](https://discourse.mcneel.com/u/davidcockey)\
**Post date:** [January 21, 2021, 2:51pm UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706/3 "2021-01-21T14:51:05Z")

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BringForward is one of the DrawOrder commands which affects the order objects on the screen are drawn. It can be canceled with the ClearDrawOrder command. It seems to me that these commands should work the same independent of display mode. [https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/draworder.htm](https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/draworder.htm)?

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<div class="post-metadata">

**Author:** ![coffsoft](https://avatars.discourse-cdn.com/v4/letter/c/5f9b8f/32.png) [@coffsoft](https://discourse.mcneel.com/u/coffsoft)\
**Post date:** [January 21, 2021, 7:03pm UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706/4 "2021-01-21T19:03:59Z")

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Hi Wim. I want to pick up on your … thought. It seems to me that if curves are displayed, their visibility should still be subject to their position in space in the context of the overall intent of the display mode. Rendered, Technical etc are display modes which are intended to block the visibility of the portion of objects which are behind others in the 2D or 3D view. Using the ClearDrawOrder might overcome this display issue, but the draw order would have been established for other valid reasons, and would then be lost. I understand that the draw order effectively overrides the position in space, but I am having difficulty understanding why it also overrides the intent of the display mode. I can understand the visibility of a curve through a surface in Rendered, Technical and similar display modes when the curve is selected. That is a useful feature.

Regards, Garry.

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<div class="post-metadata">

**Author:** ![davidcockey](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/davidcockey/32/732604_2.png) [@davidcockey](https://discourse.mcneel.com/u/davidcockey)\
**Post date:** [January 22, 2021, 6:26pm UTC](https://discourse.mcneel.com/t/curves-display-through-surfaces-differs-in-v7/116706/5 "2021-01-22T18:26:20Z")

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> [@coffsoft](#):
>
> Rendered, Technical etc are display modes which are intended to block the visibility of the portion of objects which are behind others in the 2D or 3D view.

That is how Rhino works for those display modes - unless the draw order has been changed by he user.

> [@coffsoft](#):
>
> I understand that the draw order effectively overrides the position in space, but I am having difficulty understanding why it also overrides the intent of the display mode.

Because a user may want to change the draw order of an an object in the rendered, etc display modes. Different users work differently, and have different objects and requirements.