To enable viewing of DWG, DXF, DWF and DGN CAD files using CADViewer, please proceed as follows:

The CADViewer integration with NextCloud consists of the CADViewer front-end integrated with the Nextcloud front-end inteface using VueJS with some back-end components.

CADViewer internally use php scripts to control the CADViewer CAD Converter back-end AutoXchange (ax2023_L64_xx_yy_zz), which is located in the /nextcloud/apps/cadviewer/ tree. The display process will fetch drawings from the Nextcloud file repository, use AutoXchange to convert them to SVG with CADViewer specific SVG extensions in a temp folder, and then load them into the CADViewer front-end for display and manipulation.

Note that AutoXchange (for now) is an x86 architecture and thus will not run on ARM architecture.

There are various ways CADViewer can be installed with NextCloud.

Follow instructions in 1. and then ensure permission and ownership 2. (see below) as well any rewrite rules in 4. (see below) .

Ensure permission and ownership 2. (see below) as well any rewrite rules in 4. (see below).

Modify the .htaccess file, which typically is in a structure like: /var/snap/nextcloud/38457/nextcloud/config , likely 38457/nnnnn can vary depending on linux build and Nextcloud version, below is Ubuntu 22.04 LTS / Nextcloud 27.1.3. Add the following rewrite rule (also see Troubleshooting 4.):

<IfModule mod_rewrite_c>
	RewriteCond %{REQUEST_FILENAME} !/extra-apps/cadviewer/converter/php/*\.*
	RewriteRule . index.php [PT,E=PATH_INFO:$1]
<IfModule>

Navigate to the location of the CADViewer CAD Converter AutoXchange, and provide it with chmod 750 permissions (paths below as for Ubuntu 22.04 LTS / Nextcloud 27.1.3) :

sudo su
cd /var/snap/nextcloud/38457/nextcloud/extra-apps/cadviewer/converver/converters/ax2024/linux
chmod 750 ax2023_L64_xx_yy_zz

Note 1: Likely, 38457/nnnnn can vary depending on linux build and Nextcloud version.

Note 2: Each time an auto-update of CADViewer is done, the permissions must be reset as per above.

Alternatively, follow the permission instructions in 2.

Copy the content of this cadviewer install folder and put it in the /apps/ or /extra-apps/ folder of your nextcloud installation under /apps/cadviewer/.

In a typical NextCloud installation, the installation is done with owner www-data:www-data and permissions over the files and folders in the app as chmod 750 forfiles and chmod 640 for directories. In this case you will not need to to do anything change permission of files, the CADViewer back-end will function normally under these settings.

The standard manual configuration steps from Nextcloud docs to adjust file ownership and permission, can be replicated for the /apps/cadviewer folder, so from the /apps/ folder run:

chown -R www-data:www-data cadviewer
find cadviewer/ -type d -exec chmod 750 {} \;
find cadviewer/ -type f -exec chmod 640 {} \;

Note that if you are installing under Snap the owner can be different from www-data, and the chown command must be corrected correspondingly.

If this does not get CADViewer working in your installation, please do one of the following 2A.) or 2B.) below. Also refer to 4. troubleshooting, section 5.) below.

Navigate to the /apps/cadviewer/scripts/ */ folder and execute the permission.sh script.

This script will do the recommended permission settings (chmod 750) for the relevant CADViewer folders and files.

If preferred, the user can as an alternative set these permissions manually using the instructions below:

In the NextCloud /apps/cadviewer/ folder-structure, set the recommended permissions (chmod 750) for the following files:

Execution:

/apps/cadviewer/converter/converters/ax2024/linux/ax2023_L64_xx_yy_zz

Scripts folder and files:

/apps/cadviewer/converter/php/call-Api_Conversion_log.txt
/apps/cadviewer/converter/php/call-Api_Conversion.php
/apps/cadviewer/converter/php/save-file.php

In the NextCloud /apps/cadviewer folder-structure, set the recommended permissions (chmod 640) for the following folders:

Conversion folders:

/apps/cadviewer/converter/converters/ax2024/linux/
/apps/cadviewer/converter/converters/files/
/apps/cadviewer/converter/converters/files/merged/
/apps/cadviewer/converter/converters/files/print/
/apps/cadviewer/converter/converters/files/pdf/

Redlines folders:

/apps/cadviewer/converter/content/redlines/
/apps/cadviewer/converter/content/redlines/v7/

1. Go to the applications menu of NextCloud and accept to use CADViewer as an untested application.

2. Activate the NextCloud application.

3. Success! You can now visualize your AutoCAD DWG/DXF/DWF and MicroStation DGN files with a simple click in NextCloud!

In some cases the automated update of the .htaccess file is not done. This means that the CADViewer does not connect to the back-end scripts for CAD file conversion. The user experience is that the canvas is white and the "loading.." modal will keep appearing on the screen when attempting to load a file.

1. Go to the install folder of NextCloud, this is typically /var/www/nextcloud/ (or where your installation is done), open .htaccess in a text editor. See C: above for installation using Snap.

2. Locate the rewrite rule in place: RewriteRule . index.php [PT,E=PATH_INFO:$1]

3. Add the rewrite condition before the rewrite rule: RewriteCond %{REQUEST_FILENAME} !/apps/cadviewer/converter/php/*\.*

4. NOTE: On some installations the Nextcloud apps installation folder name can change, they can be *extra-apps or custom-apps. In that case change the rewrite condition accordingly, for example RewriteCond %{REQUEST_FILENAME} !/extra-apps/cadviewer/converter/php/*\.* .

5. If needed, add both the RewriteRule and RewriteCond.

6. If the server trace gives a Warning: fopen(call-Api_Conversion_log.txt): Failed to open stream: Permission denied , then likely the current permission settings are insufficient. This case can be seen when added nginx as reverse proxy and SSL certificates on a docker container. In that case the owner may have changed, therefore try inside /cadviewer/converter/php/ to give call-Api_Conversion.php full chmod 777 permission and check if call-Api_Conversion.txt has write permissions for the owner (if you are comfortable, you can give chmod 777 on that also.). If this moves further in the process, you must also then give /converter/converters/files folder, full write permission for all owners, and also give /converter/converters/ax2024/linux/ax2023_L64_xx_yy_zz full chmod 777 permissions to perform the CAD conversions for all owners. You can also gradually change the permission process, 750, 755, 775, 777 to keep control. Always check files against other apps to see if the ownership is correct, otherwise do a chown to change ownership correspondingly for cadviewer.

You need to connect interactively to the nextcloud docker container with the command docker exec -it id_of_container (you get the id with docker ps) and once inside you need to modify the .htaccess file with vim (you install it with these 2 commands: apt-get update, apt-get install vim) and the content to put in your .htaccess is as follows:

<IfModule mod_headers.c>
  <IfModule mod_setenvif.c>
    <IfModule mod_fcgid.c>
       SetEnvIfNoCase ^Authorization$ "(.+)" XAUTHORIZATION=$1
       RequestHeader set XAuthorization %{XAUTHORIZATION}e env=XAUTHORIZATION
    </IfModule>
    <IfModule mod_proxy_fcgi.c>
       SetEnvIfNoCase Authorization "(.+)" HTTP_AUTHORIZATION=$1
    </IfModule>
    <IfModule mod_lsapi.c>
      SetEnvIfNoCase ^Authorization$ "(.+)" XAUTHORIZATION=$1
      RequestHeader set XAuthorization %{XAUTHORIZATION}e env=XAUTHORIZATION
    </IfModule>
  </IfModule>

  <IfModule mod_env.c>
    # Add security and privacy related headers

    # Avoid doubled headers by unsetting headers in "onsuccess" table,
    # then add headers to "always" table: https://github.com/nextcloud/server/pull/19002
    Header onsuccess unset Referrer-Policy
    Header always set Referrer-Policy "no-referrer"

    Header onsuccess unset X-Content-Type-Options
    Header always set X-Content-Type-Options "nosniff"

    Header onsuccess unset X-Frame-Options
    Header always set X-Frame-Options "SAMEORIGIN"

    Header onsuccess unset X-Permitted-Cross-Domain-Policies
    Header always set X-Permitted-Cross-Domain-Policies "none"

    Header onsuccess unset X-Robots-Tag
    Header always set X-Robots-Tag "none"

    Header onsuccess unset X-XSS-Protection
    Header always set X-XSS-Protection "1; mode=block"

    SetEnv modHeadersAvailable true
  </IfModule>

  # Add cache control for static resources
  <FilesMatch "\.(css|js|svg|gif|png|jpg|ico|wasm|tflite)$">
    Header set Cache-Control "max-age=15778463"
  </FilesMatch>

  <FilesMatch "\.(css|js|svg|gif|png|jpg|ico|wasm|tflite)(\?v=.*)?$">
    Header set Cache-Control "max-age=15778463, immutable"
  </FilesMatch>

  # Let browsers cache WOFF files for a week
  <FilesMatch "\.woff2?$">
    Header set Cache-Control "max-age=604800"
  </FilesMatch>
</IfModule>

# PHP 7.x
<IfModule mod_php7.c>
  php_value mbstring.func_overload 0
  php_value default_charset 'UTF-8'
  php_value output_buffering 0
  <IfModule mod_env.c>
    SetEnv htaccessWorking true
  </IfModule>
</IfModule>

# PHP 8+
<IfModule mod_php.c>
  php_value mbstring.func_overload 0
  php_value default_charset 'UTF-8'
  php_value output_buffering 0
  <IfModule mod_env.c>
    SetEnv htaccessWorking true
  </IfModule>
</IfModule>

<IfModule mod_mime.c>
  AddType image/svg+xml svg svgz
  AddType application/wasm wasm
  AddEncoding gzip svgz
</IfModule>

<IfModule mod_dir.c>
  DirectoryIndex index.php index.html
</IfModule>

<IfModule pagespeed_module>
  ModPagespeed Off
</IfModule>

<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteCond %{HTTP_USER_AGENT} DavClnt
  RewriteRule ^$ /remote.php/webdav/ [L,R=302]
  RewriteRule .* - [env=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
  RewriteRule ^\.well-known/carddav /remote.php/dav/ [R=301,L]
  RewriteRule ^\.well-known/caldav /remote.php/dav/ [R=301,L]
  RewriteRule ^remote/(.*) remote.php [QSA,L]
  RewriteRule ^(?:build|tests|config|lib|3rdparty|templates)/.* - [R=404,L]
  RewriteRule ^\.well-known/(?!acme-challenge|pki-validation) /index.php [QSA,L]
  RewriteRule ^(?:\.(?!well-known)|autotest|occ|issue|indie|db_|console).* - [R=404,L]
</IfModule>

AddDefaultCharset utf-8
Options -Indexes
#### DO NOT CHANGE ANYTHING ABOVE THIS LINE ####

ErrorDocument 403 //
ErrorDocument 404 //
<IfModule mod_rewrite.c>
  Options -MultiViews
  RewriteRule ^core/js/oc.js$ index.php [PT,E=PATH_INFO:$1]
  RewriteRule ^core/preview.png$ index.php [PT,E=PATH_INFO:$1]
  RewriteCond %{REQUEST_FILENAME} !\.(css|js|svg|gif|png|html|ttf|woff2?|ico|jpg|jpeg|map|webm|mp4|mp3|ogg|wav|wasm|tflite)$
  RewriteCond %{REQUEST_FILENAME} !/core/ajax/update\.php
  RewriteCond %{REQUEST_FILENAME} !/core/img/(favicon\.ico|manifest\.json)$
  RewriteCond %{REQUEST_FILENAME} !/(cron|public|remote|status)\.php
  RewriteCond %{REQUEST_FILENAME} !/ocs/v(1|2)\.php
  RewriteCond %{REQUEST_FILENAME} !/robots\.txt
  RewriteCond %{REQUEST_FILENAME} !/(ocm-provider|ocs-provider|updater)/
  RewriteCond %{REQUEST_URI} !^/\.well-known/(acme-challenge|pki-validation)/.*
  RewriteCond %{REQUEST_FILENAME} !/richdocumentscode(_arm64)?/proxy.php$
  RewriteCond %{REQUEST_FILENAME} !/apps/cadviewer/converter/php/*\.*
  RewriteRule . index.php [PT,E=PATH_INFO:$1]
  RewriteBase /
  <IfModule mod_env.c>
    SetEnv front_controller_active true
    <IfModule mod_dir.c>
      DirectorySlash off
    </IfModule>
  </IfModule>
</IfModule>

and then you just have to follow the instructions in the doc to set permissions on the right file and folder as per 2A: above.

1. Administrator Interface Guide.
2. User Interface Guide.

CADViewer implements CAD viewing, markup and collaboration on the NextCloud platform for AutoCAD, MicroStation, PDF and advanced raster graphics. Following CADViewer features are available in NextCloud:

• AutoCAD: Support for DWG, DXF and DWF files.
• MicroStation: Support for DGN files.
• PDF: Support for Vector Graphics PDF files. (use ... menu)
• TIFF: Support for TIFF format. (use ... menu)
• PNG, JPG, GIF: Bitmap support. (use ... menu)
• Annotation: Full redlining interface of drawings where each user has individually associated redlines.
• PDF Collaboration: Redlines/Annotation on drawings can be shared as PDF to local CADViewer-Markup folder, where the user can then share internally/externally.
• Download: Direct download of SVG or PDF image with/without redlines/annotations.
• Printing: Printing of drawings to printer driver or as PDF.
• Measurement: Global scale matrix preserved in drawing for measurement and calibration methods.
• Zoom: Advanced zoom and pan controls.
• Layers: Retained layer structure for layer management.
• Search: Integrated text search method.
• Compare: Advanced compare of drawings.

[Optional] If you are on Windows you will have to modify the file apps/cadviewer/converter/php/CADViewer_config.php to adapt the configuration to Windows (change executeable name and folders). You will also have to install the Windows back-end CAD converters. Pull the /converters/ax2024/windows/ tree from cadviewer-script-library and replace into the /apps/cadviewer/converter/converters/ tree. In apps/cadviewer/converter/php/CADViewer_config.php, update $platform and $ax2024_executable.