# \#cpp

**URL:** https://discourse.mcneel.com/tag/cpp/1903.md

[Latest](https://discourse.mcneel.com/latest.md) · [Categories](https://discourse.mcneel.com/categories.md) · [Tags](https://discourse.mcneel.com/tags.md)

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## [Update Child After RemapObjectIds?](https://discourse.mcneel.com/t/update-child-after-remapobjectids/220808)

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**Author:** [@EricM](https://discourse.mcneel.com/u/EricM)\
**Replies:** 4\
**Last updated:** [July 13, 2026, 10:51pm UTC](https://discourse.mcneel.com/t/update-child-after-remapobjectids/220808 "2026-07-13T22:51:24Z")

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I’m updating a child obj’s parent. const CRhinoHistoryRecord\* record = object-\>HistoryRecord(); if (nullptr == record) return 0; ON\_HistoryRecord\* copy = doc-\>m\_history\_record\_table.GetPrunedHistoryRecord(reco…

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## [Meshing tolerance parameter](https://discourse.mcneel.com/t/meshing-tolerance-parameter/220273)

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**Author:** [@margari](https://discourse.mcneel.com/u/margari)\
**Replies:** 2\
**Last updated:** [July 6, 2026, 8:07pm UTC](https://discourse.mcneel.com/t/meshing-tolerance-parameter/220273 "2026-07-06T20:07:04Z")

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Dear all, it is not clear to me how it is used the ON\_MeshParameters::Tolerance parameter. Documentation reported: “float: Gets or sets the maximum allowed edge deviation. This tolerance is measured between the center …

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## [RhinoMeshUnwrapper crashes](https://discourse.mcneel.com/t/rhinomeshunwrapper-crashes/217382)

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**Author:** [@Guillaume\_Chereau](https://discourse.mcneel.com/u/Guillaume_Chereau)\
**Replies:** 7\
**Last updated:** [April 14, 2026, 10:30pm UTC](https://discourse.mcneel.com/t/rhinomeshunwrapper-crashes/217382 "2026-04-14T22:30:49Z")

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Hello ! I develop several Rhino plugins for rendering and I would like to automatically unwrap render meshes that doesn’t have UV mapping set by the user. For that purpose, I recklessly used: RhinoMeshUnwrapper rhUnwr…

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## [Yak spec fails to get author, description & url from MFC plugin](https://discourse.mcneel.com/t/yak-spec-fails-to-get-author-description-url-from-mfc-plugin/217804)

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**Author:** [@Guillaume\_Chereau](https://discourse.mcneel.com/u/Guillaume_Chereau)\
**Replies:** 2\
**Last updated:** [April 10, 2026, 12:12pm UTC](https://discourse.mcneel.com/t/yak-spec-fails-to-get-author-description-url-from-mfc-plugin/217804 "2026-04-10T12:12:40Z")

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Hi ! When running yak spec command on a freshly built MFC dll plug-in, yak correctly finds the RhinoPlugInName and RhinoPlugInVersion defined with RHINO\_PLUG\_IN\_NAME and RHINO\_PLUG\_IN\_VERSION but fails to retrieve other…

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## [Opennurbs library dependencies](https://discourse.mcneel.com/t/opennurbs-library-dependencies/214950)

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**Author:** [@margari](https://discourse.mcneel.com/u/margari)\
**Replies:** 7\
**Last updated:** [January 29, 2026, 8:23am UTC](https://discourse.mcneel.com/t/opennurbs-library-dependencies/214950 "2026-01-29T08:23:36Z")

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Hello, I developed a Rhino plug-in which, of course, depends from full opennurbs.dll version (the one delivered with Rhino, capable to manipulate geometries). Now I have to add a new dependency from an other dll (calle…

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## [GeoSharPlus: Cross-Platform C#↔C++ Geometry Bridge for Rhino/Grasshopper](https://discourse.mcneel.com/t/geosharplus-cross-platform-c-c-geometry-bridge-for-rhino-grasshopper/210874)

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**Author:** [@xliotx](https://discourse.mcneel.com/u/xliotx)\
**Replies:** 4\
**Last updated:** [October 18, 2025, 3:06pm UTC](https://discourse.mcneel.com/t/geosharplus-cross-platform-c-c-geometry-bridge-for-rhino-grasshopper/210874 "2025-10-18T15:06:01Z")

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Hey Rhino community! :waving\_hand: I’d like to introduce GeoSharPlus as a cross-platform alternative to RhinoCommon for handling general geometry types (points, meshes, arrays) when you need high-performance C++ process…

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## [SubD surfaces in C++ SDK](https://discourse.mcneel.com/t/subd-surfaces-in-c-sdk/210453)

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**Author:** [@pagarcia](https://discourse.mcneel.com/u/pagarcia)\
**Replies:** 2\
**Last updated:** [October 13, 2025, 9:05am UTC](https://discourse.mcneel.com/t/subd-surfaces-in-c-sdk/210453 "2025-10-13T09:05:39Z")

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Hello, In the Rhino 8 C++ SDK, is it possible to retrieve the NURBS surfaces from a SubD cage? How does this work in practice? Is there any guide or tutorial? Thank you, Pablo

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## [Rhino C++ SDK / OpenNurbs in Package Manager](https://discourse.mcneel.com/t/rhino-c-sdk-opennurbs-in-package-manager/203114)

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**Author:** [@xliotx](https://discourse.mcneel.com/u/xliotx)\
**Replies:** 9\
**Last updated:** [October 12, 2025, 6:23pm UTC](https://discourse.mcneel.com/t/rhino-c-sdk-opennurbs-in-package-manager/203114 "2025-10-12T18:23:16Z")

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I have a Cpp lib that some of my C# Grasshopper plugin used and shared. Now I want to add support to macOS, and it seems I need to also compile it on macOS for macOS. As a windows user, this also means getting a Mac ma…

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## [New CMake Template for Rhino C++](https://discourse.mcneel.com/t/new-cmake-template-for-rhino-c/207500)

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**Author:** [@andrea.settimi](https://discourse.mcneel.com/u/andrea.settimi)\
**Replies:** 2\
**Last updated:** [September 27, 2025, 11:32pm UTC](https://discourse.mcneel.com/t/new-cmake-template-for-rhino-c/207500 "2025-09-27T23:32:04Z")

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Hello there! I just wanted to share with you cmake4rhino: it’s my take of a CMake project template for Rhino C++ plug-in development. It helps you get started quickly with a clean, reusable setup via a cookiecutter …

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## [Returning const by-value](https://discourse.mcneel.com/t/returning-const-by-value/209294)

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**Author:** [@Nikolay](https://discourse.mcneel.com/u/Nikolay)\
**Replies:** 2\
**Last updated:** [September 3, 2025, 5:09pm UTC](https://discourse.mcneel.com/t/returning-const-by-value/209294 "2025-09-03T17:09:17Z")

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Hi, const ON\_wString Name() const; what is the point of the return value constness? that is used wherever ON\_wString::EmptyString may be returned. But to what purpose ? the caller is guaranteed to get a copy here. The …

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## [SDK Rhino.Inside C++: ‘ExecuteCommand()’ and headless mode](https://discourse.mcneel.com/t/sdk-rhino-inside-c-executecommand-and-headless-mode/208135)

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**Author:** [@andrea.settimi](https://discourse.mcneel.com/u/andrea.settimi)\
**Replies:** 5\
**Last updated:** [August 13, 2025, 1:33pm UTC](https://discourse.mcneel.com/t/sdk-rhino-inside-c-executecommand-and-headless-mode/208135 "2025-08-13T13:33:05Z")

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Hello there! I am running an executable that fires commands locally with Rhino.Inside for C++ in headless mode (with the hope of deploying it in CI server): CRhinoCreateDocumentOptions options; options.SetCreateHeadles…

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## [Plugin load in headless Rhino.Inside C++](https://discourse.mcneel.com/t/plugin-load-in-headless-rhino-inside-c/208017)

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**Author:** [@andrea.settimi](https://discourse.mcneel.com/u/andrea.settimi)\
**Replies:** 2\
**Last updated:** [August 8, 2025, 12:16pm UTC](https://discourse.mcneel.com/t/plugin-load-in-headless-rhino-inside-c/208017 "2025-08-08T12:16:03Z")

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Hello there! I am trying to integrate some Google testing for my Rhino plugin in C++. This is the test I am trying to run: #include \<gtest/gtest.h\> #include "pch.h" #include "RhinoCore.h" TEST(TEST\_INTEGRATION\_Comm…

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## [Show Layers Panel Factory](https://discourse.mcneel.com/t/show-layers-panel-factory/201155)

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**Author:** [@Gabriele\_Cuccolini](https://discourse.mcneel.com/u/Gabriele_Cuccolini)\
**Replies:** 2\
**Last updated:** [July 22, 2025, 7:04pm UTC](https://discourse.mcneel.com/t/show-layers-panel-factory/201155 "2025-07-22T19:04:16Z")

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Hi, I’m working with Rhino8 and in my PlugIn I’m writing a command that requires the “Layers” panel always visible so I write this code sample that iterates all the panels and when the name is equal to “Layers” I show th…

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## [CRhinoContextMenuExtension for layer list don't work in rhino 8](https://discourse.mcneel.com/t/crhinocontextmenuextension-for-layer-list-dont-work-in-rhino-8/201971)

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**Author:** [@guillaume2](https://discourse.mcneel.com/u/guillaume2)\
**Replies:** 3\
**Last updated:** [March 26, 2025, 2:59pm UTC](https://discourse.mcneel.com/t/crhinocontextmenuextension-for-layer-list-dont-work-in-rhino-8/201971 "2025-03-26T14:59:39Z")

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Hello, i have discover that my CRhinoContextMenuExtension for UUIDLayerList didn’t work anymore. In rhino 7 right clicking on layer open my extention bellow the menu. In rhino 8 it doesn’t work anymore. I have also try…

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## [Data class instantiation and loading from document](https://discourse.mcneel.com/t/data-class-instantiation-and-loading-from-document/195736)

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**Author:** [@margari](https://discourse.mcneel.com/u/margari)\
**Replies:** 4\
**Last updated:** [December 13, 2024, 9:09am UTC](https://discourse.mcneel.com/t/data-class-instantiation-and-loading-from-document/195736 "2024-12-13T09:09:34Z")

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Hello, I have developed a Rhino c++ plug-in. My plug-in shows a tree, contained into a CRhinoTabbedDockBarDialog, which presents the data contained into a tree model. The tree model is populated with: some static el…

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## [Editable CRhinoHistoryRecord Example (C/C++ API)?](https://discourse.mcneel.com/t/editable-crhinohistoryrecord-example-c-c-api/191440)

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**Author:** [@EricM](https://discourse.mcneel.com/u/EricM)\
**Replies:** 5\
**Last updated:** [September 19, 2024, 8:41pm UTC](https://discourse.mcneel.com/t/editable-crhinohistoryrecord-example-c-c-api/191440 "2024-09-19T20:41:02Z")

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I need an example of creating a CRhinoCommand with editable history, i.e., something like \_BlendCrv. @dale has this request logged as RH-75629. In the meantime, does anyone else have a relevant example they could shar…

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## [Brep construction from polygonal mesh](https://discourse.mcneel.com/t/brep-construction-from-polygonal-mesh/186423)

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**Author:** [@design12](https://discourse.mcneel.com/u/design12)\
**Replies:** 6\
**Last updated:** [July 4, 2024, 8:58am UTC](https://discourse.mcneel.com/t/brep-construction-from-polygonal-mesh/186423 "2024-07-04T08:58:16Z")

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Hi everyone, I have a volume as a polygonal mesh constructed using CGAL, which I would like to send to Rhino as Brep via Speckle. I have gotten so far that the Brep that I get in Rhino is a closed Brep. But I think the…

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## [PointClouds with additional per point attributes](https://discourse.mcneel.com/t/pointclouds-with-additional-per-point-attributes/184144)

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**Author:** [@design12](https://discourse.mcneel.com/u/design12)\
**Replies:** 2\
**Last updated:** [June 13, 2024, 2:58pm UTC](https://discourse.mcneel.com/t/pointclouds-with-additional-per-point-attributes/184144 "2024-06-13T14:58:09Z")

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When constructing a PointCloud, adding an additional double (intensity) value per point is possible. But when I have PointClouds with more additional values, what would be the best way of adding them? Can they be added …

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## [UV editor, object visibility & ON::active\_space](https://discourse.mcneel.com/t/uv-editor-object-visibility-on-active-space/179989)

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**Author:** [@victorceballos](https://discourse.mcneel.com/u/victorceballos)\
**Replies:** 2\
**Last updated:** [May 27, 2024, 11:13am UTC](https://discourse.mcneel.com/t/uv-editor-object-visibility-on-active-space/179989 "2024-05-27T11:13:41Z")

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TL;DR Is there a way to replicate the functionality of the UV editor? (I need to add custom objects to the ‘UV space’.) Long version: Hello! I have a recurring problem and after digging through the documentation I ha…

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## [Dark/Light theme GUI changes](https://discourse.mcneel.com/t/dark-light-theme-gui-changes/180774)

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**Author:** [@dsw](https://discourse.mcneel.com/u/dsw)\
**Replies:** 9\
**Last updated:** [May 13, 2024, 7:04am UTC](https://discourse.mcneel.com/t/dark-light-theme-gui-changes/180774 "2024-05-13T07:04:44Z")

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Hi, i’m currently working on the update of our plugin to support Rhino 8. But i’m struggeling with the colors in dark mode. So i have some questions how it is done properly. Where can i get the current theme mode (dar…

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## [Rhino 8 C++ SDK 8.5 download](https://discourse.mcneel.com/t/rhino-8-c-sdk-8-5-download/180588)

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**Author:** [@dsw](https://discourse.mcneel.com/u/dsw)\
**Replies:** 3\
**Last updated:** [April 22, 2024, 8:56am UTC](https://discourse.mcneel.com/t/rhino-8-c-sdk-8-5-download/180588 "2024-04-22T08:56:26Z")

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Hi can anyone provide me the URL of the C++ SDK 8.5 download? Thanks Wolfgang

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## [Rhino C++ VS2019 Project - Crazy Intellisense](https://discourse.mcneel.com/t/rhino-c-vs2019-project-crazy-intellisense/164319)

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**Author:** [@scudelari](https://discourse.mcneel.com/u/scudelari)\
**Replies:** 2\
**Last updated:** [August 19, 2023, 3:14pm UTC](https://discourse.mcneel.com/t/rhino-c-vs2019-project-crazy-intellisense/164319 "2023-08-19T15:14:20Z")

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Hello All, I am using VS2019 and I started out with the Moose project. The thing is that the Intellisense goes crazy, finding errors all over the OpenNurbs header files. Is there anything that can be done? Importan…

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## [Rhino 8 WIP sdk](https://discourse.mcneel.com/t/rhino-8-wip-sdk/162959)

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**Author:** [@guillaume2](https://discourse.mcneel.com/u/guillaume2)\
**Replies:** 3\
**Last updated:** [July 24, 2023, 7:40am UTC](https://discourse.mcneel.com/t/rhino-8-wip-sdk/162959 "2023-07-24T07:40:35Z")

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Hello, do we have any c++ sdk for rhino 8 availlable? if yes where can i find it?

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## [Problem in divide segments for multi curves](https://discourse.mcneel.com/t/problem-in-divide-segments-for-multi-curves/159454)

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**Author:** [@Qingxiang](https://discourse.mcneel.com/u/Qingxiang)\
**Replies:** 2\
**Last updated:** [May 8, 2023, 4:53am UTC](https://discourse.mcneel.com/t/problem-in-divide-segments-for-multi-curves/159454 "2023-05-08T04:53:04Z")

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Dear All: I encounter a problem in divide multi curve object. I make a minor change based on the sample. I want to divide two curves but only one curve is divided as shown below. The code is as follows: CRhinoGetObjec…

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## [Simple way to integrate openNURBS into GH project](https://discourse.mcneel.com/t/simple-way-to-integrate-opennurbs-into-gh-project/155547)

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**Author:** [@xliotx](https://discourse.mcneel.com/u/xliotx)\
**Replies:** 6\
**Last updated:** [April 6, 2023, 1:56pm UTC](https://discourse.mcneel.com/t/simple-way-to-integrate-opennurbs-into-gh-project/155547 "2023-04-06T13:56:21Z")

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This problem has been hovering above me for a while. I’m writing a GH plugin that needs integration of cpp for data processing. I need to transfer RhinoCommon data structures, mainly Point3d, Mesh, etc. (basic types) a…

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## [Cannot select the object twice properly](https://discourse.mcneel.com/t/cannot-select-the-object-twice-properly/154548)

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**Author:** [@Qingxiang](https://discourse.mcneel.com/u/Qingxiang)\
**Replies:** 3\
**Last updated:** [February 9, 2023, 12:47am UTC](https://discourse.mcneel.com/t/cannot-select-the-object-twice-properly/154548 "2023-02-09T00:47:19Z")

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Hello, I encounter a problem in selecting the objects with two steps. First, I want to select on or more objects. Then select another one object. A simple code is below. CRhinoGetObject go; go.SetCommandPrompt(…

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## [Problem of converting wchar\_t to wstring](https://discourse.mcneel.com/t/problem-of-converting-wchar-t-to-wstring/154428)

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**Author:** [@Qingxiang](https://discourse.mcneel.com/u/Qingxiang)\
**Replies:** 3\
**Last updated:** [February 7, 2023, 6:06am UTC](https://discourse.mcneel.com/t/problem-of-converting-wchar-t-to-wstring/154428 "2023-02-07T06:06:24Z")

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Hello, I encounter a problem of wchar\_t to wstring. I tried as following, but I get a gibberish. How to convert the wchar\_t to wstring properly. Also I have anothe similar problem is how to convert a int to the ON\_wStri…

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## [How to get the model filename in C++](https://discourse.mcneel.com/t/how-to-get-the-model-filename-in-c/154391)

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**Author:** [@Qingxiang](https://discourse.mcneel.com/u/Qingxiang)\
**Replies:** 5\
**Last updated:** [February 6, 2023, 9:00am UTC](https://discourse.mcneel.com/t/how-to-get-the-model-filename-in-c/154391 "2023-02-06T09:00:21Z")

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I want to output the name of model to the text file. For example, I open a file ‘test.3dm’. Then I want export some information to a text file. How can I get the name of ‘test.3dm’ using C++.

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## [Get surfaces from document](https://discourse.mcneel.com/t/get-surfaces-from-document/153871)

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**Author:** [@margari](https://discourse.mcneel.com/u/margari)\
**Replies:** 1\
**Last updated:** [January 26, 2023, 5:39pm UTC](https://discourse.mcneel.com/t/get-surfaces-from-document/153871 "2023-01-26T17:39:29Z")

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Hello, which is the best way to obtain, from a c++ plug-in, the meshes representing all the surfaces contained in a document? Several times I need to do that in my code, but I’m always a little bit confused by the seve…

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## [Error in loading SampleCommands.rhp with Dependent DLL is missing](https://discourse.mcneel.com/t/error-in-loading-samplecommands-rhp-with-dependent-dll-is-missing/153504)

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**Author:** [@Qingxiang](https://discourse.mcneel.com/u/Qingxiang)\
**Replies:** 1\
**Last updated:** [January 24, 2023, 12:11pm UTC](https://discourse.mcneel.com/t/error-in-loading-samplecommands-rhp-with-dependent-dll-is-missing/153504 "2023-01-24T12:11:26Z")

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Hi guys, The rhino developer sample file is really good resourse for the beginner. I encounter a tricky problem. The SampleCommands.rhp can be loaded OK in the computer with Rhino SDK. However, the problem happen when I…

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