How to get a graphical model representation with standardized path coefficients?

Trine
I think you would do better to use R to write out the dot file and then run the dot program on it. You can run dot from within R using system().

I am not familiar with the model you are trying to fit but suppose you wanted to write a diagram which contained the information that you normally get from doing summary(fit)$parameters. You would save that as a dataframe and then work through the columns writing out nodes containing all the names you find in the "row" or "col" columns and then write out the paths using the information in the "row", "col" to place the arc and "name" and "Estimate" columns to label the arc. If you want to look at a primitive example of this (nothing to do with OpenMx) download the source of the latdiag package from CRAN. (Disclaimer: I am the author of latdiag).

Hope that helps.

If all your free parameters have non-NA labels, you could use:

modelOut <- mxRun(model)
parameterValues <- omxGetParameters(modelOut)
model <- omxSetParameters(model, names(parameterValues), values = parameterValues)

You need a function for each model type you create, and you probably need to label all the free parameters in some sensible fashion (I use nameRC i.e., a11 a12 etc...) . As a starter, here's one I wrote for drawing two group Cholesky models

graphViz_Cholesky <- function(model=NA, selDVs=selDVs, dotFilename="Cholesky.dot") {
	# written tim.bates@ed.ac.uk
        # e.g. call
	# graphViz_Cholesky(model,selDVs=selDVs, dotFilename="Cholesky.dot")
	omxGetParameters(model)->parameterKeyList;
	out           = "";
	variableCount = length(selDVs)/2;
	latents       = c();
	for(thisParam in names(parameterKeyList) ) {
		if (grepl("^[ace][0-9][0-9]", thisParam)) { # a c e
			from    = sub('([ace])([0-9])([0-9])'   , '\\1\\3', thisParam, perl=T);  # a c or e
			target  = as.numeric(sub('([ace])([0-9])([0-9])', '\\2', thisParam, perl=T));
			target  = selDVs[as.numeric(target)]
			latents = append(latents, from)
		} else { # means probably
			from   = thisParam;
			target = sub('(^[^0-9]+)([0-9])([0-9])', 'var\\3', thisParam, perl=T) 
		}
		out = paste(out, ";\n", from, " -> ", target, " [label=\"", round(parameterKeyList[thisParam],2), "\"]", sep="")
	}
	preOut= "";
	for(var in selDVs[1:variableCount]) {
	   preOut = paste(preOut, "\n", var, " [shape=box];\n", sep="")
	}
	rankVariables = paste("{rank=same; ", paste(selDVs[1:variableCount], collapse="; "), "};") # {rank=same; religT1; ethnicT1; raceT1 }
	latents = unique(latents)
	grep('a', latents, value=T)
	rankA   = paste("{rank=min; ", paste(grep('a', latents, value=T), collapse="; "), "};") # {rank=min; a1; a2 }
	rankCE  = paste("{rank=max; ", paste(grep('[ce]', latents, value=T), collapse="; "), "};") # {rank=min; c1; e1; e2 }
	digraph = paste("digraph G {\nsplines=\"FALSE\";\n", preOut, out, rankVariables, rankA, rankCE, "\n}", sep="");
	# cat(digraph);
	# return (out)
	if(!is.na(dotFilename)){
		cat(digraph, file = dotFilename)
		system(paste("open", dotFilename));
		# return(invisible(cat(digraph)))
	} else {
		return (cat(digraph));
	}
}

PS: You mention downloading a graphviz app, but then use the online creator: The desktop app is probably more useful.