How to control tiling of texture maps on vertical faces?

Roy Klein Gebbinck

I am experimenting with materials and texture maps and I am unable to get the map to tile properly on the vertical faces of the sample box. Only the top face looks OK, the vertical faces display a 'stripy' pattern. The examples in the Help show proper tiling on all faces of the sample box. Is there some setting for this? BricsCAD V16.2.09.

Richard Webb

 Not seeing that behavior here, although I haven't poked at all of the Redway materials and settings, yet, nor  done much with a roll-your-own material with bump maps and textures. 

brick_house.jpg

Roy Klein Gebbinck

Thank you Richard for taking the time to look at this.

Further testing shows that the problem only exists for the 'Global' material. After comparing the entity lists of several materials I find that there are quite a few 'hidden' settings for materials. One of which: 'Projection method of diffuse map' (group code 73), is the cause of this issue.

Possible values:
1 = Planar
2 = Box
3 = Cylinder
4 = Sphere

The 'Global' material uses the 'Planar' projection method, any material the user creates uses the 'Box' method.

Richard Webb

Interesting. Good detective work!

Roy Klein Gebbinck

... Maybe BricsCAD should expose the projection method for the 3 bitmaps that the user can select for a material, since this is obviously supported in the 3D renderings. And, to avoid this confusion, give the 'Global' material settings that are equal to that of a default new material.

Jason Bourhill

Hi Roy,

I raised SR50338 on MATERIALMAP support as part of producing this Bricsys TV Video. The response was:

"Have added a dev task for this.
Cannot comment as to 'if' and 'when' we will be able to address this."

It is a pity that this feature is missing, as it is really a fundamental requirement if you are serious about rendering. It is even more of a pity considering how good BricsCAD is at rendering. That said there is a lot more to MATERIALMAP than just applying a projection type. Features of the command also include the ability to move, rotate and reset the UV scale of the material map. I assume that this would require a reasonable amount of work to provide.

In the course of the producing the video above I raised over 10 support requests related to rendering. This led me to the conclusion that there can't be many users utilising rendering with BricsCAD. Perhaps if more people use it and raise requests, then it will prompt Bricsys to put more resources into development in this area. :-)

Some notes I made on using render that may be useful:

• ANTIALIASRENDER and ANTIALIASSCREEN system variables control the amount of anti-aliasing (edge smoothing) applied during rendering generation and on screen rendered mode display. Default value is 1, maximum value is 5.
  Note: Larger anti-alias values incur a high calculation cost.
• FACETRES. Adjust the smoothness of curved faced 3D solids by increasing or decreasing the number of dividing faces for shaded and hidden views. Acceptable values are between 0.01 – 10, default is 0.5. Note: Larger FACETRES values incur a high calculation cost. For EXPORT to STL format a larger FACETRES value will give better resolution (larger file size).
• FACETRATIO. In BricsCAD changing the FACETRATIO has no effect on how solid objects are displayed and rendered. In BricsCAD FACERATIO is always ON.
• Redway materials work differently to AutoCAD style material types. For Redway materials you see the message ' is a Redway material and cannot be modified' in the Drawing Explorer (you can still adjust map transformation properties). Redway materials aren't convertible to AutoCAD type, meaning AutoCAD users won't see these materials if they open the drawing.
• When rendering, unless you use a VIEW with background set, BricsCAD defaults to using the BKGCOLOR value. Note: BKGCOLOR isn't saved with the drawing.
• Global material setting works differently between BricsCAD and AutoCAD. In BricsCAD the default is to fix the Diffuse color (not Inherit), and set it to white (255,255,255). This doesn't make sense.
• A partial workaround to lack of MATERIALMAP support is to create copies of the desired material, and change map transformation values to suit.
  
• Changing the rotation map of a material causes other values to change (SR48943).
  

Regards,

Jason Bourhill

CAD Concepts

Roy Klein Gebbinck

Jason, thank you for those comments. I will definitely watch your video.

> '... change map transformation values to suit.'
Do you do this in AutoCAD or are you perhaps using a Lisp function in BricsCAD?

Jason Bourhill

Hi Roy,

>> '... change map transformation values to suit.'
>Do you do this in AutoCAD or are you perhaps using a Lisp function in BricsCAD?

I meant creating additional material types within BricsCAD. e.g. you have a wooden handrail that runs horizontally along landings, and at angles down flights of stairs. To make the grain with the handrail you would create two materials. The first would have the grain running horizontally, the second would be a copy of the first material with a different rotation applied.

To get this right, you may need to apply different material types to each face of your solid. You would probably only go to this effort if you were doing a close up render, where you would spot the difference. You can see this with my example. The grain is ok on the side, but not on other faces. However it looks ok when rendered further out.

Should of noted in my previous post, that depending on the scale of the objects of your drawing, you may need to adjust the mapping scale of the redway materials.

Regards,

Jason Bourhill

CAD Concepts

Whitewood.png

test.png

Whitewood-42deg.png