VMD-L Mailing List

From: Vermaas, Joshua (Joshua.Vermaas_at_nrel.gov)
Date: Wed Sep 07 2016 - 12:53:01 CDT

Hi John,

I thought so too, but what you get for a pure ambient material is
something gray, as though the colors aren't being applied with ambient
light. Adding in some diffuse character appears to be essential to
getting color that isn't white, black, or some shade of grey. Since
diffuse responds to the angle of incident light, I don't think VMD is
currently capable of colorful but perfectly flat shading.

-Josh

On 09/07/2016 11:32 AM, John Stone wrote:
> Hi,
> Aside from running Tachyon with the special flags, you could also
> simply use a special material and disable shadows, and possibly
> use orthographic projection get a flat unshaded 2D-like appearance.
> If you make a material that has the diffuse and specular coefficients
> set to zero, but retains a non-zero "ambient" term, when you render with
> Tachyon or TachyonInternal you should get what appears to be an unshaded
> rendering. Let us know if you have further questions.
>
> Cheers,
> John Stone
> vmd_at_ks.uiuc.edu
>
>
> On Wed, Aug 31, 2016 at 04:37:42PM -0400, Ky Wildermuth wrote:
>> Eric,A
>> What works for me is rendering with Tachyon and choosing the option
>> -lowshade such as in the example below:
>> render Tachyon $filename "/vmd/vmd-1.9/lib/tachyon/tachyon_LINUXAMD64"
>> $filename -lowshade -format BMP -o $filename.bmp
>> This is a low quality rendering option that produces no shading at all (at
>> least for the systems I have been working with). I am not sure if it would
>> make a difference but I render the images using lights 0 and 1 on (and all
>> others off) and I use the surf representation.
>> I use this to quantify areas of selections based on color via a python
>> computer vision script and it works well to identify entire selections of
>> a specific color. You can try some other rendering options if this isn't
>> exactly what you are looking for; there is a comprehensive list of Tachyon
>> options on a previous post that you can find here:
>> [1]http://www.ks.uiuc.edu/Research/vmd/mailing_list/vmd-l/23903.html
>> I hope this helps.A
>> -Ky
>> On Wed, Aug 31, 2016 at 2:52 PM, Eric Smoll <[2]ericsmoll_at_gmail.com>
>> wrote:
>>
>> Hello VMD community,
>>
>> VMD representations of chemical systems in with a style like VDW shows
>> complex shading. This shading is dependent on the lighting scheme and
>> shows the curvature of each atomic sphere. I am interested in generating
>> an image with no shading. If the system contains two types of atoms
>> coloured red and blue, the image should only contain pure red and pure
>> blue at any viewing angle. I want an image with no contrast between
>> atoms of the same type.
>>
>> Can this be done in VMD? If not, does anyone know of a visualization
>> tool that might be able to accomplish this?
>> Best,
>> Eric
>>
>> References
>>
>> Visible links
>> 1. http://www.ks.uiuc.edu/Research/vmd/mailing_list/vmd-l/23903.html
>> 2. mailto:ericsmoll_at_gmail.com